1:7 or 1:9?


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blackops
January 6, 2011, 09:20 PM
Fixing to get a Spikes LE, not sure though. Wondering (from the guys with experience) how do you like the 1:7 twist? I'm not sure what kind of diet I'm going to run this thing on, but I'll keep it inside 400yds for sure. Anyways, just looking for some opinions. Thanks guys.

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HKGuns
January 6, 2011, 09:23 PM
Really depends on what weight bullets you are going to shoot. Betting you'll be on a common diet of the very common and very cheap 55gr the 1/9 is ideal.

MMcfpd
January 6, 2011, 09:24 PM
Unless you think you'll be shooting the really light loads, as in 45 gr. or less, get a 1:7; it'll do fine with everything from 55 gr. and heavier.

migkillertwo
January 6, 2011, 09:26 PM
better for heavier loads (75gr.). 1/7 stabilizes 55gr and 62gr bullets fine.

carbine85
January 6, 2011, 09:41 PM
Best accuracy will be from the 1:9 with the more common lighter bullets. I personnely think 1:8 is the best choice.

FredT
January 6, 2011, 09:44 PM
1 in 8 gets my vote also.

Jim Watson
January 6, 2011, 09:55 PM
Yeah, but if Spike doesn't offer 1-8 it isn't much help to the OP.

1-9 will handle 69 gr match and 62 gr M855/SS109 hardball for sure, maybe 75 gr maybe not. All lighter bullets like 55 gr imitation Viet Nam era M193ish and 45 gr WWB varmint loads will be fine.

1-7 will handle up through 82 gr match, likely 90 gr (single loaded only), and the M856/SS110 tracer. It will shoot 55 gr GI, might be erratic with light varmint bullets.

blackops
January 6, 2011, 10:24 PM
As Jim mentioned Spikes doesn't offer a 1:8. I'm hearing mixed opinions here, but I'm taking it that the 1:9 should be fine just maybe a bit more accurate with the heavier bullets.

Waywatcher
January 6, 2011, 10:41 PM
If you want to reliably shoot 75-77 OTMs, which are the best thing going for terminal effect in .223, you'll need 1:8 or faster. The 1:9 twist may keyhole these.

If you want to shoot lightweights, like 40-55 at the most, get a 1:12. I don't have a use for 1:9 twist in .223.

I would definitely get the 1:7.

lobo9er
January 6, 2011, 10:47 PM
my vote is 1-7 more versatile. If anything you may shoot heavier bullets more often than 45 grain stuff. but you also may not notice. if your shooting 100 yards i dont think it matters much. depends on what you want the rifle to do.

1stmarine
January 6, 2011, 11:09 PM
Stick to the facts of ballistics and not opinions:
If you use mostly lower grain bullets (most up to 67gr) then 1:9 is perfect.
If you wan to shoot ocasionally 70gr, 75gr Hornadys or even 77gr 1:8 is perfect and still not too fast for a 50gr bullet.
If you want to shoot ONLY 70gr, 75gr and even 80gr or 90gr bullets then get the 1:7 or even a 1:6.5 but here you have a problem.
At 77gr most of the good bullets (slender high bc bullets) you are maxed out in COAL (Cartrige Overall Length) to properly feed in an AR magazine.
The 77gr SMKs and 77gr VLDs are all great but more typical in target barrels 20" and above. Some 80gr bullets and 90gr bullets need to be single feed and you also need to consider the gap before you hit the landings so only long range target shooters do this.
A 1:7 twist of rate with low grain bullets is so fast that the jackets might come apart (I have seen this and done that) and also you want the bullet to do something when it gets there so for most it is too fast.

So the ideal for the average nice upper is 1:8.

1:7 is not required only if you are always going highest grains(75 and above) and NEVER low grain like 40gr bullet.

I hope this helps.
Shoot often. Stay safe and never forget our veterans.
E.

sappyg
January 6, 2011, 11:55 PM
Wondering (from the guys with experience) how do you like the 1:7 twist?
i'm not sure exactly what the OP is asking here. the only things i've ever shot with my AR's was paper and 1/9 twist works fine for that. i've never bothered to load heavier bullets and i no longer get so involved with the bullet of the week. TMK the only reason current M4's have 1/7 twist is to stabilize a tracer round. seems to me the market is just trying to create a need in order to sell specialty bullets. that, at a premium i might add.
i've never really been so inclined to shoot anything heavier than 62 gr. bullets in an AR but then again i don't really have a specialized need to either. the matter really comes down to the intended use. beyond 300 yards and i would seriously consider a completely different cartrige.
day in day out i could be happy with 1/9 twist and not give it a second thought.

HKGuns
January 7, 2011, 12:00 AM
Popcorn time!

1stmarine
January 7, 2011, 12:03 AM
sappyg
I think you are right. If you never want to try a 70gr bullet 1:9 is better. Because I like to have hornady TAP 75gr for defense ammo I have a 1:8 but it is me. Not better or worse I am saying look at the bullet/s you want to shoot first and then decide on the system, not the other way around.
I just do not understand the need to vote in something like this. It comes to the intended purpose. I have 1:9 and 1:8 and 1:7 and others so everyone has a meaning and a purpose as I
explained above.
By overspining you loose energy as well. 1:7 will take apart some jackets in a low grain bullet specially the cheaper ones not bonded. This is a fact nothing else to discuss here.
Cheers.

FredT
January 7, 2011, 12:08 AM
I got salt and butter.

kwelz
January 7, 2011, 12:09 AM
I think you are right. If you never want to try a 70gr bullet 1:9 is better.

I have seen some 1/9 barrel have problems with bullet weight as low as 62 grains.


By overspining you loose energy as well. 1:7 will take apart some jackets in a low grain bullet. This is a fact nothing else.

I have heard this said a number of times but never seen any data to back it up.

sappyg
January 7, 2011, 12:23 AM
Popcorn time!

i'm always down for some jiffy pop. ;)

HKGuns
January 7, 2011, 12:24 AM
Pass the butter please!

1stmarine
January 7, 2011, 12:50 AM
kwelz,
Please let me better explain. lets review the facts once again.
A 62 grain is a pretty consistently sized bullet. The reason the military has the colt in the 1:7 is to be used with efficiently with the penetrator SS109/M855 as well as the marksman/sniper Mk262 (that is nothing but a 77gr SMK). A 1:8 will achieve the same. As a retired marksman I used to carry several of the SMK clips with me.

A 1:9 should stabilize the M855 but might not do harm faster in the newer with the titanium rods (a tad longer) so this is why I suggested the 1:8. I am having a hard time believing that anyone doesn't want to try a TAP round or an SMK so yet another reason for the 1:8 and The tracer will do ok. You will do fine with the 1:9 if all you shoot is the M183 (55gr federals), M855 and lower.

If you go with the 1:7 IT WILL BE OK, but just be aware of the low grain cheaper bullets SOMETIMES coming apart and the more drag on the bullet and thus lowers velocity.

I have seen some 1/9 barrel have problems with bullet weight as low as 62 grains
Look for other problems, the ammo, the barrel out of spec of something else, not the twist of rate.

I have heard this said a number of times but never seen any data to back it up.

I don't know how much shooting you guys do but even the other day one guy using a low grain bullet a jacket came a part and normally this just shows as bad accuracy but the other day it came apart at the muzzle (something that doesn't happen that often) and because he had a long brake pieces of the jacket came back flying back at us. That's why you need to make sure you always have glasses and good ones. Again a jacket coming partially a part just comes down to: Why my super nice AR cannot group s#%t with 1:7rate. ...well the answer is cheap low grain bullets with jackets that might not fully disintegrate but surely deform the bullets you are shooting.

I don't know what else I can tell you guys. There are some good books about ballistics, barrels and even the history of the AR is a nice reading and can learn about your systems.
Shoot often, stay safe and don't ever forget our veterans.

Cheers,
E.

FlyinBryan
January 7, 2011, 12:56 AM
can i ask what the popcorn thing means?

1stmarine
January 7, 2011, 12:59 AM
can i ask what the popcorn thing means?

Kids.

sappyg
January 7, 2011, 01:01 AM
I have heard this said a number of times but never seen any data to back it up.

forget the pocorn. it's a FOOD FIGHT!

Jim Watson
January 7, 2011, 01:03 AM
My 6.5 twist AR, optimized for single loaded 90 grain bullets, will definitely spin a thin jacketed bullet apart. It will blow up or bend into funny shapes even the 90 gr Sierra if loaded hot enough to reach 1000 yards supersonic. I had one target scored nothing but Xs, 10s, and misses, the latter from bullets too distorted to reach the target.
It will blow 75 gr Amax to smithereens, silver streaks in the sunlight 1/3 of the way to the target.
Nothing I have found but but a JLK or Berger VLD will take the stress of a 1000 yard load.
The SMK and Amax are fine at 600 if loaded down a bit.

If the OP wants to shoot 400 yards from the magazine, he might should be looking at the 1-7 for 77 gr length tolerant bullets.

1stmarine
January 7, 2011, 01:13 AM
Jim Watson,
Thanks for more supporting facts. The result of the twist of rate is not so aggressive in the carbine barrels but defently in a long match barrel 20 or 24" it will ALWAYS rip the small bullets apart.

This is what quick load help says about the 1:7 rate....
1:7 or 6.5 / 90 bt vld (not highly recommended unless you want to shoot the VLDs) Quick Load is a software that senior reloaders and professionals use to find the appropriate load for specific purpose. It comes with an ocean of knowledge so I wanted to post this here too.

In any case an M4 barrel in 1:7 IT IS NOT WRONG. That's why they are offering them but take into account what we are explaining above, especially if you find a great deal in old surplus 5.56. It will take them apart and your groups will suck.

There are many great 1:8 barrels out there.

Cheers,
E.

FlyinBryan
January 7, 2011, 01:16 AM
I don't know how much shooting you guys do but even the other day one guy using a low grain bullet a jacket came a part

i am assuming you are talking about 1/7 barrels?

up until this past christmas day i would have just written this off as another one of those things ive heard, but not seen, (ive actually been quite critical on this claim here in the past) but on christmas, we loaded up some 45g varmint bullets (sierra's varminter bullets). they were not even loaded to max pressure. 27g of varget, chrono'd, at 3300fps. more on that in a minute.

LOL, they looked like little grenades. anywhere from 10-50ft out they would pop and look like a little firecracker going off in mid-air. you could even hear it.

back to the chrono. we started checking velocities before we started trying to hit anything with them. (and before the 1st one "poofed")

1st one chronographed @ 3313, 3323, and the 3rd one "poofed" right over my alpha chrony and busted one of the shades......... at first i thought my brother had shot my chronograph, but as we inspected it, it looked like someone chewed up a lead fishing weight and spat it all over the inside of the chrono, and thats when we realized what happened.

we started shooting them and watching it closely, and at least every 3rd to 4th one did it. if we shot faster and warmed the barrel it seemed to get worse.

if i didnt see it i would have never believed it (ive said everything here short of calling ppl liars over the subject before. to whomever i was talkign to, my apoligies, i was wrong)

out of a 1/7 barrel, they were

HorseSoldier
January 7, 2011, 01:19 AM
The reason the military has the colt in the 1:7 is to be used with efficiently with the penetrator SS109/M855 as well as the marksman/sniper Mk262 (that is nothing but a 77gr SMK). A 1:8 will achieve the same.

Negative. 1-7 twist was mandated to stabilize M856 tracer ammo, which is lower density than M855 but longer.

Mk 262 had nothing whatsoever to do with the decision to adopt a 1-7 twist, since the decision on barrel twist came about 20 years before Mk 262 was adopted and issued to anyone.

1stmarine
January 7, 2011, 01:55 AM
1-7 twist was mandated to stabilize M856 tracer ammo, which is lower density than M855 but longer. you are right! I think it was the XM778 and since I was with Nato overseas we used the other (I think L2A1) a lot and I surely I was not there with the tracer decision lol! but I can assure you every marksman had clips with long bullets and they new how to use them with the M4s for many years before and also now. We trained for this A LOT!

If it is more important to shoot some tracers and very long bullets than any other thing then go with the 1:7 but keep in mind The 1:8 will stabilize the tracer and 75 grainers too!

Cheers,
E.

blackops
January 7, 2011, 03:11 AM
Great input guys thanks, really appreciate it. Not what I personally wanted to hear, but good information. I want the Spikes, but if the 1:7 is going to have issues with a diet of 55gr lead then I would have a problem.

What is the lowest gr you would consistently shoott through a 1:7 and be certain of no cycling issues?

Also, I don't plan on shooting 400yds. That's just the max I would push it. Another thing, one option I do like about the 1:7 is I can push to a heavier bullet and do a little hog hunting if I decide. Maybe let my nephew get a crack at a hog with it.

vanfunk
January 7, 2011, 06:15 AM
I want the Spikes, but if the 1:7 is going to have issues with a diet of 55gr lead then I would have a problem

I have never seen bullet disintegration involving 55 gr. pills out of a 1/7" twist. 40-45 gr. varmint bullets, yes, but never the 55 gr., surplus or commercial. I'd say unless you are planning on shooting the very light-weight, thin-jacketed bullets, then you are better off with the 1/7" - it's more versatile.

vanfunk

Kangspec
January 7, 2011, 07:14 AM
with 1:7 rate, you can shoot 55gr-75gr. But this does not mean anything. You need to shoot them to find out what works best for you and your gun.

lobo9er
January 7, 2011, 09:22 AM
you guys are talking light bullets not 55 grain or higher. I shoot a fs2000 1/7 twist rate it has never had a problem with any 55 grain stuff that has been shot through. I havent seen any surplus that is 45 grain so I dont think there is a worry. 1/9 is more popular because that is what is more available to the public. 1/7 cost more to produce and isn't that why its not as common? Theres not a problem with a 1/9 except you aren't gonna be able to stabalize heavy stuff visa versa with 1/7. 55 grain fmj would be fine for either.

sansone
January 7, 2011, 09:25 AM
Unless you think you'll be shooting the really light loads, as in 45 gr. or less, get a 1:7; it'll do fine with everything from 55 gr. and heavier.
absolutely agree

blackops
January 7, 2011, 09:25 AM
Thanks guys.

lobo9er
January 7, 2011, 09:25 AM
1/7 if its gonna do some light Hawg duty.

Jim Watson
January 7, 2011, 10:13 AM
Part of the specs for the 7 twist A2 was that it would handle leftover stocks of M193 55 gr.
Don't confuse a tough 55 gr FMJ with a thin jacketed varmint bullet.

Bartholomew Roberts
January 7, 2011, 10:31 AM
What everyone else has said, there is no way you would ever spin apart 55gr surplus from a 1:7 16" barrel loaded to 5.56x45 NATO pressures.

Personally, I've gone as low as 45gr WWB JHPs in my 1:7s and they do fine.

dom1104
January 7, 2011, 10:47 AM
7 twist works fine with 55 fmj.

Lots of blowhards overcomplicating things in this thread.

Millions of 55 grain shot thru 7 twist barrels in 3 gun every year without issue.

Birddog1911
January 7, 2011, 11:17 AM
Plain and simple. USGI barrels are 1/7, and they are using 62grn. bullets. I shoot 55-62grn in my 1/7 BCM, and it is quite accurate for a carbine.

Plan to shoot lightweight varmit bullets; 1/9. Don't plan to shoot anything but 55-62; either will serve you just fine. There is some good info in this thread, but don't get too caught up in it.

blackops
January 7, 2011, 12:33 PM
Great information guys. Think I'm going to go with the Spikes 1:7. Seems like a smaller company that is dedicated to qc and offers it for a reasonable price. Chromed out too, so that 1:7 is going to have a good life span.

onebigelf
January 7, 2011, 12:46 PM
Both of mine are 1:9. They'll put 69gr SMK handloads into frighteningly small holes. They are superb with the common 55 and 62 gr military loads. They did NOT like the 75gr Wolf. It comes down to what you are going to shoot. Are you going to be feeding it 55 and 62 gr ball? The 1:9 is perfect. Are you going to be handloading heavy bullets or buying specialty heavy rounds? Get a 1:7.

John

Creature
January 7, 2011, 01:02 PM
I have shot competition with an armory-issued 1:7 (which was dedicated competition gun built by NAVSEA). I personally own a 1:9 and a 1:8. I prefer the 1:8 for most loads.

RockyMtnTactical
January 7, 2011, 02:17 PM
I have both.

1/7 works better with higher grain bullets, 1/9 works better with lighter varmint type bullets.

TonyAngel
January 7, 2011, 03:58 PM
I do have both and have had many of both. Personally, I think you're over thinking it. Really, what is kind of cracking me up is that in most threads where guys are asking about the quality of ARs, the same names keep coming up as being on the top. Companies like Spike's, Bravo Company, Noveske, etc. The part that's cracking me up is that all of the "better" companies only offer their "battle" rifles with a 1:7 twist.

Now it's looking like this poor guy that's trying to buy a rifle is being made to second guess his choice because of the posts in this thread. The fact of the matter is that 1:9 is a fast twist too. It's really fast. If you want a varmint rifle to shoot the light stuff, up to around 55gr, 1:12 is all you really need. Maybe even 1:14.

The bottom line is that a good barrel is a good barrel. I have a 1:9 that does fine with 77gr bullets and a 1:7 that will shoot bug holes with 52gr match hollow points. Based on numbers alone, it can be argued that a 1:9 twist will shoot the lighter stuff better, but in practice, I haven't seen it. I'll go out on a limb and say that a 1:9 should shoot trash ammo (M193, M855, SS109, etc.) better than a 1:7, but not appreciably better. You'll likely need to measure the groups with a caliper to be able to tell the difference.

BlackOps, if you like the Spike's, get it. It's a darned nice rifle, especially for the price. As for light bullets exploding, I've seen it; but it was only with light skinned varmint rounds that aren't cheap in the first place. My point being that if you are going to spend money on really good, purpose specific ammo, you may as well be buying the heavier stuff to shoot in your rifle.

You should also keep in mind that every barrel is different. You can't just say that a barrel with a 1:7 twist is going to do really well with 77gr bullets. You also can't say that 1:9 is going to do really well with 55gr bullets. I've seen and had 1:7 barrels that much preferred 52 and 55gr bullets and 1:9 barrels that hated 55gr bullets.

Just quit worrying about it and buy the rifle that you like. You could do a lot worse than a Spike's. For what it's worth, my current goto AR is a 14.5" 1:9. I recently discovered a little stash of Nosler 77gr bullets that I had forgotten about. I loaded them up to feed the little 1:9 carbine and at 100 yards, picking off clay pigeons hasn't been a problem.

Kwanger
January 7, 2011, 04:23 PM
I think for all intents and purposes, for most people who stick to mainstream ammo (i.e. 55gr and 62gr) - either twist rate will be just fine. If now or in the future you have an inclination to shoot light varmint rounds, err on the 1/9 side. If now or in the future you will likely be more inclined to go towards shooting 75gr Sierra Match Kings at distant targets, the 1/7 is more the ticket.

SpaceFrank
January 7, 2011, 05:51 PM
I think if I were going to get one, it would probably be a 1:9". The reason being that most of my range time would be spent throwing 55gr. FMJ, because they are available and cheap. I would certainly think about shooting 75gr. HD loads, but in a HD situation, I doubt the possible instability would play a huge role in the 30 foot maximum distances in a house.

Now if I planned to hunt with 75 gr. bullets, that might be a different story.

blackops
January 7, 2011, 08:42 PM
I've come to the decision to run 55gr projectiles to punch paper with. If I do decide to hunt with it, I'll push to 70 plus and reload something nasty. Hunting with this rifle will be few and far between, though. Again gentelmen, all of you have really helped, and I'm greatly thankful for sharing your wealth of knowledge.

1stmarine
January 7, 2011, 09:35 PM
I am surprised you didn't go crazy but glad that somehow we were able to help.
As someone posted before it is hard to go wrong with any reputable well price upper these days.
Cheers,
E.

carbine85
January 9, 2011, 08:44 PM
I'll stick with what I said earlier, the 1:9 is more practical. For a carbine length barrel and the ammo you are most likely to shoot the 1:9 should provide better accuracy overall.

P-32
January 9, 2011, 09:28 PM
I shoot NRA Highpower. The more common twist is 1 in 7 because we shoot 80 gr bullets loaded 1 at a time at 600 yards.

I had dreams of shooting 90 Gr bullets out of my AR at 1K. My first AR has a 6 1/2 to 1 twist. Now that it has a bunch of rounds through it, It's used as a loaner or it's what I shoot at the reduced matches. I was afraid I would be blowing up the 52 and 53 gr SMKs at the 100 yard matches. I've not had problems. The rifle shoots well enough using the light SMK's to win me money and matches.

My vote is for the 7 to 1 twist. I have not tried the light SMK's through my Kreiger 7 to 1 as I won't put bullet wear on this barrel because I use it for full across the course matches.

christcorp
January 27, 2011, 12:03 PM
The whole 1:7/1:9 twist subject gets way too humorous. Unless you're into shooting competitions, at long range, the whole "Twist vs bullet weight vs stabilization" is way over rated. Some people talk about bullets "Key Holing" in the target. "SO WHAT!" Again; unless you're a marksman shooting competition, or a paid black ops sniper; "Who cares?"

You can shoot a 75 grain bullet perfectly fine out of a 1:9 twist barrel, out to about 300 yards; and hit your target. If you're a marksman and need/want that 1 MOA at hundreds of yards, then yes, barrel twist is an issue. So will the type of ammo you use. But for the 90% of AR owners, what seems to be the problem? Do you think the rifle will malfunction? It won't. Do you think your aim will be off so much that you won't hit your target? It won't. Do you think you'll have problems feeding or ejecting? You won't.

Again; unless you're into some sort of competition shooting, or simply really like to try and hit a silver dollar at 300 yards, a 75 grain bullet in a 1:9 barrel is not a problem. Of course, there are those that believe in the red-dawn scenarios and think they'll be getting into a "Gun-Fight". Well, I can't convince them that they won't, so I won't try. But for the majority of shooters, it's not an issue. As for self defense, let's be real. If you wind up in court, trying to justify shooting someone at 100+ yards (Probably even 50+ yards); and claiming that it was "SELF-DEFENSE"; you're going to have a very hard time winning that argument. So the whole bullet weight vs barrel twist is a total non-issue for the overwhelming AR owners.

Me personally; I don't usually shoot 75 grain bullets because they cost more. "If you can find them". I don't reload the .223, but I have shot a lot of 75 grain reloads. A friend of mine reloads them, and we plink with them. I plink normally with <$4 a box ammo. He likes to reload. To each their own. But at 200 yards, my M&P with 1:9 twist and my Saiga .223 with 1:10 twist both hit the target with 75 grain bullets. Are the bullets "Key Holing" at the target? Hell if I know. I couldn't care less. I'm not a competition shooter. Suffice it to say, that unless you're into some marksmanship type long distance competition; or shooting prairie dogs or coyotes at 300 yards, the whole Bullet weight vs barrel twist is a non-issue.

Water-Man
January 27, 2011, 12:31 PM
Spikes is fine. Go with a 1:7 twist.

blackops
January 27, 2011, 12:38 PM
Chris, I'm not into competition and I don't get paid to shoot anything period. This will just be my first AR and I want to be sure of what I'm getting into before I fork out 1500 for it. I got the Spikes 1:7. I'll plink with 55's and reload 75's if I plan a hunting trip.

Robert
January 27, 2011, 12:41 PM
Popcorn time!
If you do not have an opinion on the topic at hand please do not post trivial things just to up your post count.

I have a 1:7 barrel on my AR and it seems, so far, to run very well. I have used 62gn hand loads in it and had excellent results. I am looking at 69gr match bullets for my competition use. A bit of over kill for what I do but compared to loading 308, 223 is cheap.

I have not tried 55gr or lighter in it yet, but from everything I can gather it should shoot just fine. If I can get out to the range I will let you know. But my vote is for 1:7 too.

Robert
January 27, 2011, 12:45 PM
I'm not into competition
Are there any tactical rifle matches in your area? They are great fun and a great way to learn how to run your rifle. And did I mention they are more for than should be legally possible?

Usagi
January 27, 2011, 01:09 PM
Some generalizations:

1. If you intend to shoot mostly 55-gr to 62-gr bullets (which are generally the most common and least expensive commercial ammo), then I suggest a 1:9 barrel. Accuracy will be no different, but the 1:9 barrel is most often cheaper.
The 1:7 barrels are generally more expensive, and will not add any accuracy until you get to heavier bullets (70-gr+).

2. If the 1:7 is the same price, and you do not intend to shoot bullets under 55-gr, then by all means, get the 1:7.
Do not think it is a magic potion for accuracy. More HP shooters prefer a 1:8 twist (usually 69-gr to 79-gr bullets), and folks that go longer like a 1:6.5 twist (and 90-gr+ bullets).

3. If you plan to regularly shoot bullets 70-gr and over, get the 1:7 (or a 1:8).

4. If you plan to regularly shoot under 55-gr bullets, get the 1:9 (or a 1:10 or 1:12).

TonyAngel
January 27, 2011, 01:16 PM
I believe that by limiting yourself to 1:9 twist, you will be excluding some fine rifles as options. ALL of the better rifles, BCM, Noveske, Spike's, Larue, etc. come with 1:7 twists and are not available (as far as I know) in a 1:9. 1:7 shoots 55gr projectiles just fine.

GCBurner
January 27, 2011, 02:10 PM
My Colt 20" HBAR came with 1:9, so I've had the chance to actually experiment a little, with both commercial loads, surplus, and handloads to see what it likes best. The surplus SS109 62gr loads are kind of the baseline, they shoot little groups at 100 yards consistently. The 55gr. surplus FMJ are almost, but not quite, as small. Handloaded 55gr Hornady flat-base hollowpoints group as well, or better, but the 55gr boattail bullets are not quite as accurate. I got some 63gr Sierra PSPs, and they shot acceptably for me, pretty close to the SS109s, but the 69gr Sierra Match Kings don't seem to like my rifle, for some reason, and I haven't been able to find a load with them that matches the plain NATO surplus stuff. Your mileage may vary.

christcorp
January 27, 2011, 02:26 PM
Chris, I'm not into competition and I don't get paid to shoot anything period. This will just be my first AR and I want to be sure of what I'm getting into before I fork out 1500 for it. I got the Spikes 1:7. I'll plink with 55's and reload 75's if I plan a hunting trip.
Blackops; I understand what you're saying. And while I personally would never pay $1500 for an AR, you have to decide the purpose of buying the gun. If you plan on mainly punching paper at 100-200 yards and using it for defensive purposes, then it will never matter at all if it's a 1:7 or 1:9 twist. Any bullet from the 55g to 75g will do exactly what you want it to. If you plan on shooting varmints, prairie dogs, coyote, targets, etc... at 300 yards, then your accuracy probably needs to be much better. Therefor, a 1:7 would be a better choice if using the heavier bullets. I shoot prairie dogs a lot. Small little critters. But I usually use 55 or 62 grain bullets to do that. At normal paper punching distances; and home defense; I don't care if the bullet is 55g or 80g, it will still hit your target at those distances.

But you already bought your AR, and it has a 1:7 twist barrel. So it doesn't really matter what is said here. You have what you have. My comment is more intended for the individual who hasn't bought their rifle yet, but are looking. Those of you in this situation, DO NOT WORRY about any of this barrel twist stuff, unless you plan on shooting competition, marksmanship, etc... or you plan on hunting with the 75-80 grain bullets at the 300+ yard mark. That's the only time when the barrel twist mast become significant. For the <300 yard shots; shooting targets; and defensive purposes, the barrel twist doesn't matter. The heavier bullets will work just fine in any of them. So; if you happen to find the rifle you like, but it has a 1:9 barrel; don't discard that rifle as an option and automatically spend hundreds of dollars more on a rifle that has a 1:7 twist. It's not that important.

Bartholomew Roberts
January 27, 2011, 02:37 PM
You can shoot a 75 grain bullet perfectly fine out of a 1:9 twist barrel, out to about 300 yards; and hit your target. If you're a marksman and need/want that 1 MOA at hundreds of yards, then yes, barrel twist is an issue.

Actually, when I tested this many years ago out of my Bushmaster 1:9 16" HBAR, I didn't have that experience. I got about 4-5" at 100yds with Black Hills 75gr Match ammo. At 200yds the groups were around 20" and we ran out of ammo before we could push it to 300yds and test that out.

That is going from memory of course; but the original post of those results is in the archives here somewhere. However, I'd hesitate to say that any 1:9 will shoot 75gr just fine out to 300yds in every instance, though I don't doubt there are 1:9 barrels that are quite capable of it.

christcorp
January 27, 2011, 04:27 PM
Actually, when I tested this many years ago out of my Bushmaster 1:9 16" HBAR, I didn't have that experience. I got about 4-5" at 100yds with Black Hills 75gr Match ammo. At 200yds the groups were around 20" and we ran out of ammo before we could push it to 300yds and test that out.

That is going from memory of course; but the original post of those results is in the archives here somewhere. However, I'd hesitate to say that any 1:9 will shoot 75gr just fine out to 300yds in every instance, though I don't doubt there are 1:9 barrels that are quite capable of it.
A lot depends on the ammo; but also sights. If you're trying to hit >100 yards with open iron sights or 1x Red-Dots, then you'll be lucky to hit anywhere near the target. (Not saying that you are). But when I've sighted numerous rifles in at 200 yards, I've been able to hit the target at 300 yards with 70+ grain bullets. Am I going to get those 1-2 MOA that some people want? Nope; not going to happen.

But i have to keep emphasizing what the gun will be used for; and whether or not you want to spend the extra strictly for the 1:7 twist barrel instead of a 1:9. Where I live, big game hunting: Antelope, Deer, Elk, Moose, Sheep, etc... is NOT ALLOWED to be shot with anything smaller than a .243. So, I'm not going to use an AR for hunting large animals. So, what other reason would I NEED a 75 grain bullet? Honestly; I can't think of one possible reason that I would need a 70-80 grain bullet.

1. Self Defense? No. Self defense isn't done at 100+ yards. Jury probably wouldn't even buy the self defense argument at 50 yards. So assuming you did use the 1:9 barrel for Self Defense, it wouldn't matter what size bullet was it it. It would hit your target.
2. Target Practice? No. If I'm going to shoot paper, I'm going to shoot the cheaper 55 or 62 grain. Matter of fact; I usually shoot steel case russian ammo at <$5 a box.
3. Varmint, Rabbit, Prairie Dog, Coyote, etc...? No. No matter what twist barrel I had, I'd want to use the lighter 55-62 grain bullet anyway.

The only reason I can even imagine using 70-80 grain .223 bullets is either: Large game hunting; which I'm not ALLOWED to do, or competition shooting which requires highly accurate match type ammo; which I'm not into.

So my original advice still stands for the majority of potential AR owners. Don't spend the extra for the 1:7 barrel if it will cost you more if you're not into competition shooting, or plan on shooting past 300 yards and in both cases you feel you NEED the larger bullet for match or hunting. Each person has to answer this question for themselves. "What Would I Use a 75 grain Bullet For"????? If you feel you would need to use a 75 grain bullet, the next question has to be: "Will I be shooting at 300 yards and need the type of accuracy I get at 100 yards"? If the answer is yes, then get the 1:7 barrel. if the answer is no, and you can get the same quality of barrel for a significant savings if it's in the 1:9 barrel; then think hard about it. I got my M&P15 on sale last month. Retail was $1069, but final price after sales and rebates was $649. At that savings, I didn't care if it was 1:7 or 1:9 Hell, I can buy a complete new upper and still be at less than the original price of the M&P. So again; decide what you're going to use the rifle and possibly a 70-80 grain bullet for, and at what distance, and you'll know what and how much to spend on a barrel.

Bartholomew Roberts
January 27, 2011, 04:46 PM
I've shot out to 600yds with this particular 16" 1:9 HBAR, so I feel comfortable with the platform and its ability to perform with lighter loads. At the time I did this test, a typical 5rd group of Santa Barbara SS109 from the bench would be under 2".

However, I do not consider 4-5" with match ammo at 100yds or 20" at 200yds to be acceptable performance - and the 200yd performance is pretty much unacceptable for any use. So I am taking issue with your statement that heavier bullets are just fine under 300yds in all 1:9 barrels. They aren't fine in every single 1:9 barrel, though some 1:9 barrels do perform well with them.

As a result, I think your premise regarding "Will I be shooting at 300 yards and need the type of accuracy I get at 100 yards"? " is fundamentally flawed since I think there are 1:9 barrels out there that won't deliver that kind of accuracy with heavy bullets at 200yds, let alone 300yds. Otherwise, I think you have a good, practical analysis going.

TonyAngel
January 27, 2011, 06:19 PM
How about this for a monkey wrench in all of the theories. I had a White Oak barrel with a 1:7 twist that shot its best groups with 52gr HPs. You just never can tell, really. I know of at least two ARs with 1:9 twist barrels that will hold right at MOA with 77gr SMK handloads. There will always be exceptions to the rule, I suppose.

HorseSoldier
January 27, 2011, 08:02 PM
1. Self Defense? No. Self defense isn't done at 100+ yards. Jury probably wouldn't even buy the self defense argument at 50 yards. So assuming you did use the 1:9 barrel for Self Defense, it wouldn't matter what size bullet was it it. It would hit your target.

Mk 262 seventy-seven grain ammo is very lovely stuff for a fighting rifle, but I agree with the above point entirely -- civilian self defense shootings occur at a range where none of the performance it yields will matter. Honestly, at self-defense ranges you could shoot 62+ grain ammo through a 1-12 twist barrel and would tend to get acceptable results (i.e. hits on a bad guy or bad guy sized target) even if the group sizes would look embarrassing on the flat range.

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