converting an ar-10

[Coondog]

got a dpms lr-308 that is just the basic model from dpms. I am looking at converting this rifle and i think i want to convert it to a 338 federal cartridge. This seems like an enticing round and should have a good knock down. I have not made up my mind yet on this subject. I am looking for something big and good for long range. I've seen the 50 beowulf or something like that but it sure seems like that aint much of a long range cartridge. If anyone has any suggestions as to what other calibers that this ar-10 could be turned into that would be 338 or larger that is what im interested in i want the biggest thing i can make out of this.

I am under the assumption that i may only need to change the barrel to become a .338 federal. The only thing i am unsure of is if the upper reciever is strong enough for the pressures. I dont see why it wouldn't be seeing as how it is only a necked up 308. Thanks in advance to all.

 

[Coondog]

well i guess there is nothing interesting about my thread. boohoo. maybe its bc i dont have a big ennough member status or something. huh well i know someone knows something about .338 federal if anyone does i'd appreciate the opinion.

 

[Texas42]

Sorry, don't know anything about AR-10's or .338 federal. : (

 

[Coondog]

so is there any kind of benefit of having a 338 over a 308? is that the niggest caliber you can go with on an ar-10? thats the biggest one i have seen advertised so far.

 

[M. Sage]

What exactly are you going to use this for? The problem is that the AR-10 or DPMS long-action AR platforms are going to be somewhat limited in how much power you'll be able to wring out of the rifle. It also matters if you already have an AR-10.

Basically, it's going to come down to compromising between long range and big bore. If you want long range, go with 6.5 Creedmore (DPMS sells complete rifles). If you want a harder-hitting hunting round at the expense of long-range performance, go with the .338 Federal. Best of all worlds? .308.

 

[Coondog]

so in all reality improbably screwing the pooch by doing a caliber swap huh? I was wanting to do something odd and not as often seen, something for fun. But i'd really like something that is bigger than a 308 in the ar platform. I sure do like it. And there are so many different things you can do to the rifle itself. Is 338 fed the biggest claiber that can be put in the ar-10 rifle?

 

[Coondog]

so the 6.5 creedmore has more distance than the 308? or are you just comparing it the the 338 fed? Like i said i just want something different. Only one true purpose it would be for is the ability to shoot as well as some of these older guys still using time proven ammo with a newer round. And maybe my wife could shoot a deer with it, other than that just something to screw around with.

 

[outdare]

I looked at the ballistics chart provided. The difference I see in the 6.5 and the .308 SST rounds are small. The .308 round looks to carry more velocity at 500 yards than the 6.5, but I am just a novice at this.

As far as the DPMS is concerned, I have an LR-308 AP4 the carbine version. From my understanding you will not just be able to change the barrel. You would most likely have to change the upper to achieve the results you want. Have you considered difference of the cost of the ammo between the .308 and the .338? You would be stepping up to more expensive round. If you want a long range gun, I would recommend a bolt in the .338, 6.5 or other caliber of your choosing.

 

[outdare]

Ha! DOH! my mistake. Like I said I am a novice at the ballistic's.

 

[IXLR8]

It seems the purchase was made in error. Perhaps you should have purchased a Barret, or other purpose built long range semi-auto. Don't butcher a good gun to make a potentially dangerous to operate weapon. Engineering a change of this magnitude is beyond the casual tinkerer. However if you are an experienced gunsmith, then have fun!

 

[Texas1911]

It seems the purchase was made in error. Perhaps you should have purchased a Barret, or other purpose built long range semi-auto. Don't butcher a good gun to make a potentially dangerous to operate weapon. Engineering a change of this magnitude is beyond the casual tinkerer. However if you are an experienced gunsmith, then have fun!

You aren't going to be endangering anything by going to a .338 Federal over a .308. In all actuality a 180 gr. .338 Federal would have a superior pressure curve than the same 180 gr. load in a .308, due to the case to bore ratio.

The .338 Federal is a necked up .308 which gives you a far superior bullet in my opinion (.338) for hunting purposes. For long range shooting, the .308 is a superior load-out compared to .338 Federal, but we are talking beyond 300 yards here. The 6.5 Creedmore doesn't do anything that warrants the caliber, if you want an accurate gun ... build a 6.5-284 or 6.5x47 or .260 Ackley, etc. bolt rifle. I don't see the point to 1000 yard semi-autos, you aren't really doing anything faster at that point.

 

[M. Sage]

I don't see the point to 1000 yard semi-autos, you aren't really doing anything faster at that point.

You won't have to take your head off the gun or your sights off the target... any more than recoil will cause, anyway. Should speed up target acquisition. Should also be less likely that you have to change position to cycle and reload the rifle, too.

 

[Coondog]

like i said earlier in my post i just like the ar platform, i like its furniture options, its feel, recoil, semi-auto, everything about it. I just want it in something different than .308 Sounds like a 6.5 cm wont be a dangerous swap to me and should be able to reach out there and touch with it. I could opt for a diffferent type of gun on this project but thats just what it is. I have decided i want to convert this rifle to whatever i can rather trhan buy a bolt rifle and i am thinking the 6.5 sounds real nice.

 

[M. Sage]

Just buy the whole upper.

Now the question is, do you have an actual Colt AR-10, or something else?

 

[Texas1911]

You won't have to take your head off the gun or your sights off the target... any more than recoil will cause, anyway. Should speed up target acquisition. Should also be less likely that you have to change position to cycle and reload the rifle, too.

I don't have to change positions to cycle a bolt-rifle, especially a short action. If you have to move out of the way of the scope then you need to reinvestigate your scope mounting because the eye relief has you too forward on the stock.

 

[Texas1911]

Just buy the whole upper.

Now the question is, do you have an actual Colt AR-10, or something else?

Colt built an AR10 for the commercial market?

Also, the 6.5 Creedmore would be a good cartridge for reloading, something you should really look into if you want to do alot of shooting on even a moderate budget.

 

[M. Sage]

Colt built an AR10 for the commercial market?

Also, the 6.5 Creedmore would be a good cartridge for reloading, something you should really look into if you want to do alot of shooting on even a moderate budget.

Oh, ooops. Armalite. Too used to the AR-15 market. :/

 

[Texas1911]

Oh, ooops. Armalite. Too used to the AR-15 market. :/

I was about to say, don't think I've ever seen one ... that would be rare!

 

[SC-Texas]

The 6.5 bullet has killed hundreds of thousands of NAATZees, commies and anyone else who crossed the frontier uninvited.

that same bullet is used for large mammals of the 4 legged kind extensively in Europe.

Frankly, the 6.5 is probably better than the 7.62 at killing mammals.

It also offers better BC for long range shooting.

 

[e4for2]

I see DPMS offers 260 rem 243 308 338 6.5 on their 308 platform