Question for DPMS "308" & "7.62" shooters about these chamberings & accuracy.

V

VaniB

New member
Question for DPMS "308" & "7.62" shooters about these chamberings & accuracy.

DPMS has chambered some of it's AR15 platform rifles in the 7.62 chambering, and others in the 308 chambering.

I understand that while it is OK to shoot the ".308Win" in a "7.62" chamber, it is not advisable to do the reverse and shoot the military 7.62 in a 308 chamber due to the 7.62 higher pressures. The DPMS rep told me that the amount of freebore is also different in the two barrels.

I'm an accuracy nut, and it is important to me to get the best accuracy with hand loads out of the rifle that is possible. I prefer to keep the factory barrel if it is capable of 3/4" -7/8" or so MOA accuracy, rather then to buy the rifle with the intent of rebarreling it.

Will either DPMS chambering deliver this kind of acuracy with handloads? Or, will one chambering be more inclined then the other to deliver better accuracy? I plan to use 308 Win handloads in both chamberings.
 
As I have stated before, the DPMS LR-308 that I bought shot 5in. groups @ 100 with all handloads and "match" factory offerings. DPMS told me tough stuff. Didn't try any 7.62 loads though, might not should have traded it.
 
bisley said:
I think you have got it the wrong way round buddy.....
[/URL]
Click to expand...

Thanks for bringing that to my attention. This was information straight out of the mouth of Evan over there at DPMS. I even wrote it down on paper as he was speaking. Perhaps he was getting confused with the fact that the military 5.56 has higher pressures then the .223

This is not a good scenario for me. I already bought a new AP4, and didn't realize it's chambered to shoot crude military ammo through it. Not sure I want to go $475 for a Noveske barrel, or a $400 Krieger barrel that will not even have a bolt to mate up to it.

3/4" -7/8" MOA accuracy would do fine. I'm not looking to take a 16" AP4 into tournements.
 
I have a DPMS LR308 AP4 and it will shoot at the accuracy level you desire quite regularly with Federal 168 gr match ammo. The best hand load so far is 40.5 gr. IMR3031 and 168 Seirra's.
I don't mean to imply it will shoot to this level without fail, but often enough to impress the hell out of ya.
Regards,
John
 
John, my dilemma is that I didn't realize that the 7.62 chambering is quite different then the 308 chamber, and I'm told that 308 Win brass will not last too long before case head seperation occures.
 
Using commericial brass I initially had some problems with pressure at "loading mannual" max loads. Reducing loads a bit corrected the pressure problems. The issue seems to be that most manuals list loads for bolt guns and they seem to generate too much pressure for gas guns. As stated earlier I have settled on the one hand load w/ IMR 3031 and 168 Sierra's. I have loaded some commercial cases 4 x's and had no case head seperation issues. I did have some blown primers initially but not since reducing loads.
Hope this sheds a little light.
Regards,
John
PS Check this site http://www.6mmbr.com/308win.html for more on 7.62 vs .308
 
Last edited by a moderator:
John, I'm going to stick close to your recipe for starters since you've arrived at the accuracy I desire.

What 308Win brass have you had the best results with? What dies are you using? I assume that for reliable operation you are fully resizing the case...... or are you just bumping the shoulder back a bit?
 
I'm using Win and Fed brass, that does not mean it's the best but it's what I have. Absolutely full length size...I'm using RCBS small base dies to insure reliable feeding, and Rem 91/2 primers for an extra measure of safety against slam fire possibilities. (they're a bit harder)
I suggest you start out below my load as I only know it's safe in my particular gun.
my gun also has a JP Enterprise trigger system (crisp 4#) and a DPMS muzzle brake. Yes, it really works well. I'm sure you'll enjoy your AP4 just work slowly and carefully and enjoy the process of finding what it likes. Keep me posted on your results.
Regards
John
PS IMR 4895 also shows good signs..Rememer start low
 
John,
I'm surprised to hear that you are using small base dies. That's good info to know.

I would have thought that full length sizing with regular 308Win dies would have induced all the reliable feeding you'd ever need, being that the commercial 308Win brass that you are using is a few thousandths shorter then the military 7.62 brass to start with.

It will be a good while before I ever fire my AP4 or other DPMS rifle(s) that I intend to buy. I'm in panic buying mode and am more concerned for the time being with just buying and aquiring them before it's too McBama late. I've got a 22x47Lapua bolt action project going right now.

Thanks for the usefull info. If you're getting that kind of accuracy with the 7.62 chamber, then I should be able to as well...and won't let "7.62" markings on the barrel stop me from making a purchase. Thanks again.
 
You must log in or register to reply here.
Back
Top