IS 308 R25 DPMS 16" BBL, too short for standard loads?

Sounds like a lot of guys using ar's. It's going to be like shooting a short barreled 357 with h110. Lighter bullets with faster powder would possibly reduce the light show....

Honesty will be the best policy even if your friend doesn't want to hear it. His rifle simply isn't built for the purpose he intends. It is built for slinging M80 ball or similar at big targets and relatively close range. He'd actually be better served with a match/varmint AR .223 Wylde from Rock River or similar. With a 75 ELD-M it will be a solid 600 yard performer and good enough to be interesting to 1000.

I think you're on the right track with 150 grain bullets and 4064. It will be a flame thrower with any powder. You could try BL-C2 or CFE223 if you can find it and load at M14 service speeds. This should make the flash and blast a little less severe. This is what I did with the CETME and G3 clone I used to own. I was able to stabilize the 155 Nosler BTHP and get respectable accuracy at 300M. On a calm day the accuracy held up farther out, but that bullet wasn't really designed to buck the wind.

I have experience loading for short barreled .308... for my 16" M1a. As Random 8 suggests, it's not really made for big bullets at long distances, it just isn't. Having said that, you can coax it into giving reasonable performance to about 300yds... IF the rifle is up to the task. That suggests a fairly rigid barrel bedded into a lapped receiver in the case of the AR. I know, I built one.

As far as load choices... for 110grn to 150grn bullets, try IMR3031 or TAC. I regularly use IMR3031 for both 110grn Hornady V-Max, which is a very good bullet for a 16" .308, and any generic 150grn FMJ. The 110grn bullet over IMR3031 makes the big AR feel like you are shooting and AR-15... so that might be an avenue for you. You will not likely get maximum velocity with IMR3031, compared to something like IMR4064.

Moving to 168's... I go to IMR4895 or IMR4064. I've gotten better accuracy out of IMR4064, but there is that blast thing. FWIW, TAC also gave me very good results with the 168grn SMK in my 24" Savage model 10, so I'm going to try it in the M1a, too, just to see. You can try IMR3031 in the 16" with the 168's, but the velocity won't be there like it would with IMR4064, but it should mitigate some of the blast.

Bullets will make a difference. Shooting the 168grn Nosler CC next to the 168grn SMK... the SMK wins every time... in both rifles... so it's my suggestion to start there, unless a hunting bullet is needed.

If you (he) is willing to spend a little money and time on it, you can likely improve it. Pulling the barrel, lapping the receiver, and then bedding it with Loctite compound will help... but if the barrel is a spaghetti noodle, you are still going to be short. I don't know about the stock... but replacing it with a more rigid stock shouldn't be too expensive. The trigger...? A competent gunsmith familiar with AR's should be able to work on the trigger at least enough to get the creep out of it.

Good luck.

Yeah try something like H322, RE10x, imr3031 maybe RE7, AA2460 and lighter bullets, like 150 and lighter.
A trigger like a shot gun sounds like you need a better trigger. I can see my gun with a heavy trigger moving up to 1moa trying to get it to break.

A 16" barrel, vs longer:
- won't wear any faster
- won't fail to spin a heavier bullet
- won't be inherently less accurate

It will be slower, and more so with heavier projectiles (vs lighter). At range, Slower has similar effects as the above, but it all comes back to muzzle velocity.

16" .308 is going to throw some fireballs with powders on the slower end (4064& Varget). May be less with something in the benchmark to 4895's range. It's going to be hard to push anything heavier than a 150 very fast in that short of a barrel.

I like the Speer 125 gr TNT HP in my .308 AR with 18” barrel. It chronographs around 2900 FPS with just under 48.0 gr of TAC and is decently accurate for a Palmetto State Armory PA-10 gen 1. Also have had decent results with the Nosler 155 gr Custom Competition with 36.5 gr of Reloder 10x, but it was pretty slow, around 2450 FPS. My initial efforts with my standard 24” bolt gun load (168 gr Nosler CC with 42.5 gr of IMR-4064) were disappointing, but that was when the gun was brand new. More recent efforts with the Speer 168 gr OTM bullet and 43.0 gr of IMR-4064 have been more promising, but still feel the 18” barrel handicaps the heavier bullets. I really like those Speer 125 gr TNT bullets, accurate, affordable and available (occasionally).

Here is my DPMS LR308 18" Bull Barrel. Changed out the trigger to a Geissele SSA, along with an A2 stock. I'm loading 43.5 GR. of RL-15 under Sierra 168 GR. HPBT Match bullets. Excellent accuracy couldn't be happier. The weight is my only complaint. This is heavier than the M14, I toted around Germany 1965-67.

My DMPS Gen II Recon with a heavy 16" barrel is a tack driver. I chronoed five 168 AMAX bullets over 40.8 gr of Varget recently with a mangentospeed and they averaged 2,336 fps. Five of the same rounds out of a 24" Armalite AR10 gave 2,522 fps. This load is technically a reduced load (Hodgdon lists 42 gr as start for a 168 gr SHPBT and 46 as max) so there's lots of room to work up according Hodgdon but I'm using lake city brass so who knows how far from start and max I actually am. Anyways, it's sub MOA in both rifles but it's pretty slow in the 16" barrel (with 40.8 gr of Varget at least).
That slowness got me working on 125 gr .308 bullets specifically for the 16" barreled rifle. I recently Chronoed some speer 125 gr TNTs at an average MV of 2,894 fps with 45.1 gr of AR Comp. That was the most accurate load at around .54 MOA. AR Comp is hard to come by these days though so I'm going to try to get similar results with Tac, Varget and BLC2 as I have lots of that. Still, that AR Comp load was very compelling.
Incidentally, I also chronoed the 125 gr Nosler BT. 48 gr of TAC gave an average MV of 2,869 fps. Accuracy was terrible at 48 gr. The same load was 3,089 fps out of the 24" barrel Armalite AR10.

ACES&8S said:

But let me tell you, even in the daylight, behind the gun I can tell it is a FLAME THROWER.

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Yep a 16" 308 is.

ACES&8S said:

Here is my opinion, a 16" BBl isn't made for heavy bullets in .308, it will WEAR the
weapon down as well as be difficult to keep consistent groups.

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Nope short barrels will group just fine.
It depends on what he's calling long range 800 is easy peasy with a 16" 308, but 1000 is tricky you have to run it very hard and that means flame thrower. I fixed that problem by sticking an old Gen5 OSS suppressor on my 16" 308. Nice thing is being a reflex it's only an inch longer than a standard birdcage.

the different barrel length will not change the reload data but it will impact the velocity you get.

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https://hodgdon.com/faq-items/does-my-shorter-barreled-rifle-require-different-reload-data/

A 223 barrel at 14.5" uses the same load data as a 24" barrel. Just the velocity is different.

If the muzzle flash is troublesome , use a powder with a flash suppressant.

ACES&8S said:

It is one of those
deals where I am going to have to tell him it just isn't worth trying to make it a long-range bear rifle, which is
what he imagines, but still having a short barrel for up close action, which is like he should also put a
bayonet on it if he is that afraid of target animal.

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Not to sound like CPT Obvious, but... why not just spin a new barrel on it? He wants a long-range, heavy bullet rifle, stab a 20" heavy profile barrel on it and call it a day.

243winxb said:

use a powder with a flash suppressant.

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'Suppressant' ...is not eliminator. A 16" barrel with a slower powder IS going to give you some blast, no matter.

mavracer said:

Nope short barrels will group just fine.

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A short stiff barrel is actually known to be very conducive to accuracy in fact due to experiencing less barrel whip and possibly less harmonic inconsistency.
From RifleShooterMag.com: Shorter, stiffer barrels tend to vibrate more consistently and are probably more accurate on average.
and from a fairly rigorous study published at The TruthAboutGuns.Com-The Truth about Barrel Length, Muzzle Velocity and Accuracy
The results of this study were very telling. Overall, as demonstrated in the accuracy charts, the shortest barrel length provided the most consistent accuracy across the board and the longest length proved to be the least accurate with the same loads.

redcon1 said:

A short stiff barrel is actually known to be very conducive to accuracy in fact due to experiencing less barrel whip.

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I don't think that's what the OP is talking about... the barrel on his friend's rifle is likely a lightweight profile barrel, and likely not assembled with much care. You put a big honkin' barrel on it, like CaptHank shows in his photo... sure, there will be some accuracy potential there. Spend a little time and lap the receiver, and use a bedding compound to mount the barrel, even more potential.

Here is the 16" .308 I built up for a friend of mine. It has a BA heavy 16" mid-length barrel on it. I simply lapped the receiver and torqued the barrel down, and we were getting 1" at 100yds with generic M80 surplus... which I consider pretty good right out of the box. On another build... a 22" heavy 6.5CM build... I had to add bedding compound to stabilize the barrel, even though I lapped the receiver, it now shoots sub-MOA if I do my part.

Charlie98 said:

I don't think that's what the OP is talking about... the barrel on his friend's rifle is likely a lightweight profile barrel, and likely not assembled with much care.

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I didn't gather that but, regardless, a short barrel is generally conducive to good accuracy and, everything else being equal, it can and will outshoot a longer barrel but at a cost of velocity. Nice rifles btw. An AR10 build is on my list of things to do next but I'm still having plenty of fun with my AR15 build and my other AR10s.

Charlie98 said:

Spend a little time and lap the receiver, and use a bedding compound to mount the barrel, even more potential.

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I have the lapping tool but I can't get ahold of any aluminum oxide lapping compound and I'm hesitant to use silicon carbide so I skipped lapping the receiver and the rifle was still able to hold around .66 MOA with the 25.3-25.7 gr of Varget and Sierra 69 gr HPBTs without any kind of real break in. That's with a 20" Shilen barrel and a triggertech diamond trigger and an aero matched receiver set. I didn't bed the barrel into the receiver either. It wasn't so tight that it required thermofitment but it was a near perfect fit. I was pleased. I just torqued it down without a lot of drama and it shot well.

ACES&8S said:

Here is my opinion, a 16" BBl isn't made for heavy bullets in .308

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In the article I linked to, the 175 gr bullets out of the 16" and 18" barrel both outshot the same 175 gr bullets out of the 26" barrel from 200 yards-900 yards. What's more, the heavier bullets showed less change in velocity between the 16" and 26". In fact, the 175 gr bullet showed the least difference-only 8%. The author of the study tuned the powder charge to each barrel length apparently. I'm still a fan of lighter high BC bullets in 16" barrels but this graph makes a pretty compelling argument for the use of 175 gr bullets in 16" barrels.

redcon1 said:

I have the lapping tool but I can't get ahold of any aluminum oxide lapping compound and I'm hesitant to use silicon carbide so I skipped lapping the receiver and the rifle was still able to hold around .66 MOA with the 25.3-25.7 gr of Varget and Sierra 69 gr HPBTs without any kind of real break in. That's with a 20" Shilen barrel and a triggertech diamond trigger and an aero matched receiver set. I didn't bed the barrel into the receiver either. It wasn't so tight that it required thermofitment but it was a near perfect fit. I was pleased. I just torqued it down without a lot of drama and it shot well.

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On the first AR-10 build, the .308, the barrel to receiver fit was quite tight, and I thought there was a good chance it wouldn't need bedding... which it did not. The second build, the 6.5CM, the barrel to receiver fit was not very good, and the receiver extension was seriously out of true. I lapped it down, but I didn't want to get stupid with it, so I bedded it, too.

redcon1 said:

I didn't gather that but, regardless, a short barrel is generally conducive to good accuracy and, everything else being equal, it can and will outshoot a longer barrel but at a cost of velocity. Nice rifles btw. An AR10 build is on my list of things to do next but I'm still having plenty of fun with my AR15 build and my other AR10s.

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I had a DPMS (.223) Oracle that had a spaghetti noodle for a barrel, and I have a friend that has a R25. I was not impressed with the assembly or components of either, although the R25 seems to function pretty well, very often not a given. I'm using an educated guess that the OP's rifle is a 'lightweight carbine' of sorts, with a lighter barrel, and assembled en masse with little attention to fit. It probably has the free float forearm, but that in and of itself may not be enough to make it a good shooter.

Personally, I am a short-barrel convert... both in pistols and rifles, with rare exception. I really like my 16" M1a, and it works for 90% of what I want it to do; exploring the limits of it's accuracy at longer ranges is only a natural progression, although it's a theoretical exercise for me. My 24" heavy barreled Savage model 10 will likely get rebarreled with an 18" barrel when the time comes. Short barrels CAN shoot, but nothing is free... the load has to be tailored to the rifle for sure.

This is an interesting thread to me. I just recently got a stripped upper and lower DPMS style. Mine will be for paper shooting at 500 yds. max. It seems as though 18-20" barrel would be my goal.

Charlie98 said:

On the first AR-10 build, the .308, the barrel to receiver fit was quite tight, and I thought there was a good chance it wouldn't need bedding... which it did not. The second build, the 6.5CM, the barrel to receiver fit was not very good, and the receiver extension was seriously out of true. I lapped it down, but I didn't want to get stupid with it, so I bedded it, too.

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Yeah, I probably got lucky but I was also buying quality components. For my AR10 build, I'm thinking aero precision matched receiver again and a 18"- 20" high quality barrel, possibly CF wrapped. If it looks like I need to lap it or bed it, I will but I don't want to do it unless I really need to. I'm 90% settled on another .308 but 7mm-08, 243 win and 6.5 Creedmoor are all tempting too BUT then I keep thinking that if I'm going to build another rifle in a non-NATO standardized caliber, I really should be thinking about 6mm ARC and do the AR10 build later. So I guess I'm still mulling it all over while having fun shooting what I already have. And then, of course, there's the .277 Fury to think about.

Charlie98 said:

Personally, I am a short-barrel convert... both in pistols and rifles, with rare exception. I really like my 16" M1a, and it works for 90% of what I want it to do; exploring the limits of it's accuracy at longer ranges is only a natural progression,

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Yeah, I'm starting to see that light too.

redcon1 said:

What's more, the heavier bullets showed less change in velocity between the 16" and 26".

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That's always been my experience whether a 3" 9mm 115 vs 147 or 12.5" 5.56mm 55 vs 77gr.
I had a DPMS SASS barrel on my 308 for a while and absolutely hated it gun was just way to heavy. Switched to the Faxon big gunner and love it.
To me a 16" AR and a good mid weight barrel are peanut butter and jelly, but they're a jack of all trades master of none.

redcon1 said:

I really should be thinking about 6mm ARC and do the AR10 build later.

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I just wish the 6mm ARC was out before I got so invested in the Valkyrie, but since I have the Valkyrie and a 6mm Creed AR10 not sure what I'd do with the ARC.

Not sure how it being a semi-auto has anything to do with it, but 16"-18" 308 barrels do just fine from bolt guns. Yea, you're shooting a LITTLE slower, but not nearly as much as a lot of folks think. About 20" is nearly ideal for 308. You have to go to 26" or even longer to see any measurable gains in velocity over 20".

A 16" barrel will be no more than 150 fps slower than 20" and probably closer to 100 fps. Changing to a faster powder doesn't help. All of the powder will burn in 6-8" anyway. Faster powder may need 6", slower powder may need 8". But the load that produces the best MV from a 26" barrel will also be the load that is fastest at 16". Choosing a faster burning powder is only helpful from pistol barrel lengths. The powder you choose could affect the reliability of a semi auto so that may be a consideration.

To shoot a 308 at 1000 requires some hot loads, fired from an obscenely long barrel. Typical loads from 20"-24" barrels start running out of gas at around 800 yards. From a 16" to 18" barrel 800 might be a bit too far. Most semi-autos are not as accurate as most bolt guns. Semi-autos usually won't function reliably with hotter loads, so you're limited to using mid-level loads in a less accurate rifle. The way I see it those factors are the real limiting factor. A longer barrel probably won't help.

I've got a bit of data from my 3 .308 rifles; they are... the 16" M1a, a 22" Savage 99, and the 24" Savage 10TAC.

Shooting Radway 150grn surplus, I got...

M1a: 2625fps
99: 2700fps
10: 2850fps

168grn Nosler CC over 41.5grn IMR4895...

M1a: 2400fps
99: 2450fps
10: 2650fps

168grn Federal GoldMedal Match

99: 2525fps
10: 2710fps

It's interesting to see that there is a larger margin between the very close 22" Savage and the 24" Savage, rather than between the 16" M1a and the two Savages, but I put that down to the differences in the Savage 99's barrel more than anything.

jmr40 said:

A 16" barrel will be no more than 150 fps slower than 20" and probably closer to 100 fps. Changing to a faster powder doesn't help. All of the powder will burn in 6-8" anyway. Faster powder may need 6", slower powder may need 8". But the load that produces the best MV from a 26" barrel will also be the load that is fastest at 16". Choosing a faster burning powder is only helpful from pistol barrel lengths. The powder you choose could affect the reliability of a semi auto so that may be a consideration.

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According to QuickLoad, it is very rare that all of the powder will burn within the full length of a rifle barrel, and the slower the powder, the worse it (generally) gets. While it's true that a slower powder will generally produce the most MV in any given barrel length, the benefits of a faster powder take over the shorter the barrel gets... at least in my experience.

I load for the .348WCF. Using the Montana 200grn gas-checked cast bullet, and fired out of my 20" Browning 71...

63grn H4831, 2150fps
44grn IMR3031, 2150fps

Granted, this was with cast bullets, so the dynamics of jacketed would likely be different. The muzzle blast was so bad with the H4831 load, the shooter next to me would walk off the line until I was done, not so much with the IMR3031 load... although that is not to say there was not some blast, for sure. The IMR3031 load produced better accuracy (subjective, of course...) and used nearly 1/3rd less powder, by weight, while reaching the same MV, all at nearly the same estimated Pmax. Plugging my numbers into QuickLoad... but changing to a standard 24" barrel... things change a bit, and the slower powder starts to pull away.

Switching to 33grn IMR4227, I get a MV of 2000fps, and a 5rd ES of 8fps. Yes, this load of IMR4227 burns completely in the 20" barrel, which is why I got such good SD numbers I believe. And, again, I'm using nearly 50% less powder than the H4831 load, getting 90% of the velocity of either of the other loads... and it really only hurt me when I got past 500yds, where I ran out of elevation. However, I don't like IMR4227 for semi-autos because of the pressure spike to get reliable functioning, although with the .308 and lighter bullets that might not be an issue. I don't know, I've never tried it.

Unless your barometer is absolute muzzle velocity, I believe faster powders work better overall with shorter barrels, and particularly with sub-20" barrels in cartridges like the .308 where the advantages of a slower powder diminish. Not only are they more economical, but they typically produce less muzzle blast... one of the items the OP mentioned. As always, every rifle is different... so a faster powder may or may not produce the best accuracy, just like anything else in the handloading chain.