69 vs. 77 SMK and other questions


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TonyAngel
August 16, 2010, 03:43 PM
I've been reloading .223 for a short while and am still experimenting. I've pretty much settled on RL15 as my powder. It's readily available locally and I've gotten good results. I was previously loading progressively using a Dillon setup, but noticed that I was getting as much as .4gr deviation in the charges. So...I bought a Hornday Auto Charge.

After having used the Auto Charge, I'm finding that it considers a charge of .1gr over to be acceptable, but will set off an alarm if it goes .2gr over. So essentially, all of my charges are between 24 and 24.1gr. My question is, will that .1gr make much of a diffference in accuracy. If not, I'll just keep using the Auto Charge. If so, it'll be faster for me to return the Auto Charge and go back to throwing and weighing each charge and using a trickler.

My next question is with regard to SMKs for .223. I've been using the 77gr SMKs with good results. I shoot out to 100 yards about 85% of the time and have been told that 100 yards is too short of a distance for the 77gr pill to stabilize. Is this true?

If I go from the 77 to 69gr SMKs, will I have to re-adjust my seating die? I'm just asking, because if I will, I'll just get another tool head and set of dies so that I don't have to mess with my settings.

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NuJudge
August 16, 2010, 04:45 PM
I have no experience with the 77gr in .223. I have a lot of them, I just have not gotten around to shooting any. I have a lot of experience with 50, 52, 69 and 80gr in the .223, all of it good. I have some experience in the .223 with 75gr bullets, all of it bad.

This shooting season, I have been shooting RL-15 with both 69 and 80gr SMK bullets with excellent results. I don't believe you will see a difference on paper between 24.0gr and 24.1gr. I have been shooting 24.0gr with 69's in Winchester brass, with R-P 7.5Match primers.

If you are only shooting to 100 yards, can I suggest you switch to 52gr bullets, 26.5gr 748 and CCI primers? They always shoot little knots, and the 748 meters a bit better for me. In low wind situations, this load still shoots little knots at 200 yards.

As to 69 vs 77gr OAL, it ought to be about the same with the same settings. The ogive looks very similar on the two.

dagger dog
August 16, 2010, 04:59 PM
Twist rate determines stability, so you need to know what the twist is on your rifle, the SMK69 was designed for the 1 in 9 inch twist rate.

TonyAngel
August 16, 2010, 05:06 PM
Any particular reason that you suggest the light projectiles for the shorter ranges? I'm trying to stay away from 748. The weather changes a lot down here and I'd like to stick with something a bit less sensitive to temps. As for that 69gr SMK load that you quoted, that's the exact recipe that I tried ten rounds of yesterday. First group measured jut over .5" and the second just over .7"

I don't usually shoot such low round groups. I typically shoot ten round groups, but I only had ten rounds. I was asking about the 77s stabilizing at short distances because I like to standardize on one load, if I can. If there is no reason not to shoot the 77s are close ranges, I'll just stick with those.

Since I have settled on one flavor of the SMK or the other, I'm trying to decide which to go with, because I want to order a lot of it and just be done with it for the next year.

Thanks for all of the info.

W.E.G.
August 16, 2010, 05:14 PM
What shooting game are you playing?

National Match course?

I can promise you that 0.1 grains powder in .223 won't make one iota of difference in performance.

You need to adjust your seating plunger any time you change bullets.
If you are loading to allow all the rounds to fit in an AR15 magazine, the seating-depth issue is not complicated.

Canuck-IL
August 16, 2010, 06:55 PM
I think the 77s will stabilize by 100, assuming a 1:8 or quicker barrel.
69s vs 77s - to keep them all at mag length (I use 2.25) you need just a very tiny adjustment on the seater die.
Most of those shooting 69s, 77s (75s) and 80/82s across the course use the 52s for reduced course matches - very accurate and a few $$ cheaper.
If the alarm tolerance on the pwoder dispenser is .1, then your loads are 23.9 - 24.1 ... tolerance can be up or down. You'll never see the difference between those extremes on paper, especially not at 100 yds...at 600, maybe but at that point you're segregating cases by weight, neck turning, etc. so powder variations can appear more prominently.
/Bryan

TonyAngel
August 16, 2010, 07:40 PM
Thanks Canuck. The dispenser I'm using tolerates .1gr over, but will set off an alarm at .2gr over. It won't dispense under the 24gr that it is set for (unless it is due to the scale being off) so all charges should be between 24 and 24.1gr. I'm going to quit being so anal about it and just let the dispenser do it's job.

Last question, as a general matter, when shooting out to 100 yards, are the lighter, 50 something grainers going to be more accurate than the heavier bullets? Or is shooting the lighter bullets simply a matter of saving a bit of money?

Eb1
August 16, 2010, 07:58 PM
Shooting a 77 grain SMK @ 100 yards is not needed in my opinion. The reason for the 77 MK in .223 is BC for 600 yards plus shooting.

I bet you get better groups at 100 with a 69 grain SMK. jmo/experience.

Jim Watson
August 16, 2010, 08:26 PM
I know it gets tiresome to hear, but you will not know without shooting the gun.
I have a 9" twist .223 that is more accurate with 52s than 69s. And a 12" twist .223 that is more accurate with 60s than 50s. Empirical testing rules.

Canuck-IL
August 16, 2010, 08:42 PM
Last question, as a general matter, when shooting out to 100 yards, are the lighter, 50 something grainers going to be more accurate than the heavier bullets
Not necessarily ... but maybe :) It really depends on the twist and that particular barrel's preferences. I've seen a couple of 1:9s that would tolerate 75s and a bunch more that wouldn't. A lot of 1:9s kind of poop out at the 62s.
/B

wanderinwalker
August 16, 2010, 09:01 PM
TonyAngel,

My belief is that using the lighter bullets (52/53/60gr range) at 100-yards saves wear on my match barrel. Whether or not it is significant, I don't know. But it makes me happy... And they are a bit cheaper, as is the ball powder I fuel them with. ;)

As for the 69/77 at 100 yards, they can both shoot really well up close. The idea of the bullets not settling in at 100 yards is really with the 75-90gr long range bullets, as far as I understand it. I don't bother shoot 80gr loads at less than 200-yards, and I don't get super concerned about their grouping until I hit 300+. (Side note, my loads with 80gr Noslers and Varget shoot really, really nicely at 300 yards.)

But at 100-yards, NuJudge gave you the load. 26.5gr of 748, CCI primer (I used 450s because I have a bunch of them) and a 52.

Somebody will be along to post better results, but this is how this load shoots for me using the Nosler bullets. The shots out the left are me. This is not even same-headstamp brass and the powder charges were just run through a Lee Perfect Powder Measure. Ball powder just flows so well.

http://i3.photobucket.com/albums/y92/P-990/016.jpg

TonyAngel
August 16, 2010, 11:57 PM
Thanks guys. I think I'm going to settle on the 69gr SMKs as a middle of the road compromise.

Sorry that I didn't mention the specs on my barrel. It's a 16" 1:8 twist. I just had it stuck in my head that the 77s might not be the best choice for 100 yard shooting due to stabilization. I just went back through my pics (the ones that I bothered to take) and found some .5" groups that I shot with some 69s. That's probably an indication of what they're capable of in my rifle.

dboyles
August 17, 2010, 08:36 AM
I'm in a similar boat as I have an AR-15 with a 16" 1:8 stainless barrel. I have mostly shot 69 and 77 SMKs, and 75gr Hornady Match BTHP. Varget is my powder of choice since it works well in my Chargemaster, produces good groups, and is relatively temperature-insensitive. All of them produce honest sub-MOA 5-shot groups at 100 yards. And I'll tell you, the biggest gains I've seen have come from using Lapua brass. It's expensive, but if you amortize it over half a dozen (or more) loadings it's a little easier to stomach.

I might have to give the 52gr SMKs a try, but I don't feel like trying half a dozen different powders to get the results that I'd like. I'd be interested to hear about a good load with the 52 SMK and Varget.

REL1203
August 17, 2010, 09:03 AM
I have a 1:7" twist DDM4, and am trying to decide if I should go with 69 or 77 SMKs myself.

NuJudge
August 17, 2010, 03:52 PM
The reason for the lighter 52gr bullet is that it can shoot better than any of the others we're talking about, until the wind starts rearing its ugly head, which happens beyond about 100 yards.

During the Winter, I shoot on a 200 yard range with big trees on both sides, and the wind always from behind. Effectively there is no wind. Fifty-two grain bullets and 748 with CCI primers easily shoots "clean" Service Rifle targets with high X counts in Sitting and Prone Rapids.

CDD

TonyAngel
August 17, 2010, 04:21 PM
I don't know what happened. I got on Midway's site to order the 69s. I could have sworn that I put a couple of boxes in my cart. I checked out and everything. This morning I had an email stating that my order has been received. Just killing time, I checked the invoice and it says that I ordered the 77s. Must have been a sub conscious thing.

I'm actually breathing a little easier knowing that this coming weekend's shooting will be having fun and not testing loads.

I'm getting to be so fickle about settling on a load. Since I already have the 77s coming in, I think I'm going to give getting some Varget a try. I've never used much of it because it didn't flow too well through my powder measure. Now that I'm using the Hornady Auto Charge, that won't be an issue any longer. I'm seeing everywhere that Varget is people's first choice with RL15 running a close second.

For you guys in a situation similar to mine, I have been shooting 77gr SMKs and they DO group sub MOA out at 100 yards. I'm just exploring possibly tightening that up a bit more, just for the heck of it.

I have shot 20 round groups using 77gr SMKs over 24gr of RL15 that were pretty nice. I shot one three weeks ago that measured 1.2" for all 20 rounds with 15 of the 20 going into .7". Considering that the group consisted of one big hole and the five that went side, I'm thinking it was me that screwed it up. My point is that you should have good luck with the 77s.

ForneyRider
October 19, 2010, 01:38 PM
After reading some with 1:9tw barrels can shoot the 77 SMK just fine, I picked some up. I haven't loaded them yet. I can shoot 69gr SMK and 75gr H-BTHP just fine. Sierra offers 50cnt box which makes it easier on pocketbook.

I use AA2230, R15, and Varget with the heavier bullets in .223.

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