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View Full Version : Whats the differance between a PRS for a AR15 and a AR10?



mstennes
05-17-11, 14:40
I just picked up a MWS, with a 20" stainless barrel, I want to swap out the SOPMOD for a PRS, I happen to have a PRS laying around, but its for a AR15, I know the buffers are different as well as the spring, but IIRC the buffer tubes are the same, (I hope) as I have a exrta rifle extension also. I see they have two different models one for the 10 and one for the 15, but the standard and collaspable buttstocks are the same also, right?
Thanks

jbo723
05-17-11, 16:16
From my understanding, the buffer tube needed for a PRS needs to be an A2 rifle length. I have one on my AR10 and it came off of my AR15 so I believe that is the same. I had to use the Armalite buffer and spring though specifically for the AR10.

mstennes
05-17-11, 16:31
From my understanding, the buffer tube needed for a PRS needs to be an A2 rifle length. I have one on my AR10 and it came off of my AR15 so I believe that is the same. I had to use the Armalite buffer and spring though specifically for the AR10.

That's what I thought, I know you need the heavier spring and buffer, but my receiver extension is the same as my carbines and the SOPMOD stock is also the same as my other LMT MRP's

stevie
05-17-11, 16:35
The longer charging handle of the AR-10 may hit the cheek weld on the AR-15 PRS stock.

chadbag
05-17-11, 16:40
The difference between the PRS for the 223 guns and the 308 guns is the checkpiece on the 308 guns is shorter to allow for the longer travel of the charging handle on 308 guns.

Buffers and springs etc are irrelevant to the PRS differences. Yes, the 308 guns may use different springs and buffers but those are not part of the PRS. If you replace a fixed stock on your 308, use the same spring and buffer that came with the gun, whether or not you use the 223 or 308 version of the PRS.

Duffy
05-17-11, 17:35
Right you are, Chadbag. The AR10 PRS's cheek piece is so far back to be of much use.

I use an AR15 PRS on my AR10, my SN3 doesn't require but a few turns on the cheek piece adjustment to raise it a little, so the charging handle still clears the cheek piece.

http://i75.photobucket.com/albums/i314/Duffypoo/AR10-1.jpg

mstennes
05-17-11, 18:27
Right you are, Chadbag. The AR10 PRS's cheek piece is so far back to be of much use.

I use an AR15 PRS on my AR10, my SN3 doesn't require but a few turns on the cheek piece adjustment to raise it a little, so the charging handle still clears the cheek piece.

http://i75.photobucket.com/albums/i314/Duffypoo/AR10-1.jpg

Ok gotcha, then the AR15 is the one I will use, no sense in buying another one.
Thank you

apg06
05-17-11, 19:26
mstennes, if it helps I remember someone telling me that if you have the wrong model PRS (ex. AR15 version being used on an AR10) you can call Magpul an get the correct cheek riser.

Duffy
05-17-11, 19:44
Hm, I'm pretty sure that's not going to work. The cheek piece sits on a recessed area of the stock so when it's all the way down, it's flush with the top of the stock. The AR15 PRS cheek piece is longer and sits closer to the charging handle than the AR10 PRS, which has a shorter cheek piece and sits further back.

Top, painted one is the AR15, the black unpainted PRS stock is for AR10. The AR10's cheek piece appears to be bigger but it's just an illusion because it is closer to the camera. Note the area below the cheek piece that's relieved so when the cheek piece is dialed all the way down, it sits flush with the top of the stock. If you put an AR15 PRS cheek piece on an AR10 PRS, I don't think the cheek piece can be dialed all the way down, there's no relieve in the stock to accommodate it.. And since it's still further back, I don't think it'll help that much even if it worked.

http://i75.photobucket.com/albums/i314/Duffypoo/PRS.jpg

apg06
05-17-11, 20:01
I just finished browsing the Magpul website for any information that would confirm what I had been told and found this on their AR15 PRS page,

"NOTE: The PRS is a direct replacement for an A1 or A2 fixed stock. Fitting to a Carbine will require a Rifle Receiver Extension tube, Rifle Buffer and Spring (not included). DO NOT USE THE PRS AR15/M16 ON AR10-TYPE RIFLES DUE TO CHARGING HANDLE CLEARANCE ISSUES! Please order the the AR10/SR25 PRS: PRS Precision-Adjustable Butt Stock – AR10/SR25. Contact Magpul at 1.877.4MAGPUL if you need to convert your current PRS stock to the AR10/SR25 model."

This doesn't explictly state that the cheek riser is the part(s) needing to be replaced for the conversion but I don't see anything else on the stock that would hinder the path of the charging handle.

Duffy
05-17-11, 20:40
The cheek piece clearance is the only reason. If you have to raise the cheek piece to such height to obtain a good cheek weld, then I'd look at different rings.

My ARMS rings were slightly lower than the LT mount, which made it necessary to adjust the cheek piece a little.

Dozer
05-17-11, 21:12
You will need to replace the cheek riser and tube in front of it.

jbo723
05-17-11, 21:28
Right you are, Chadbag. The AR10 PRS's cheek piece is so far back to be of much use.

I use an AR15 PRS on my AR10, my SN3 doesn't require but a few turns on the cheek piece adjustment to raise it a little, so the charging handle still clears the cheek piece.

http://i75.photobucket.com/albums/i314/Duffypoo/AR10-1.jpg

Duffy, do you run your .308 suppressed? I only ask cause I see the SF brake..If so, what buffer are you running? I have a 18" Noveske with a AAC 762SD and I was getting double feeds when running 168-175gr ammo using the standard Armalite buffer. I just bought the Slash heavy buffer but, I haven't had a chance to test it out yet.

Duffy
05-17-11, 22:11
I can't run it suppressed (therefore some over spray of paint on the brake I didn't wipe off :jester:)

I was looking for a good brake for the AR10, as with an A2 compensator there was a lot of muzzle flip. The SF brake does a good job, but nobody around me enjoys it the way I do lol.

I have Slash's buffer in another AR10 that runs an AR10 spec carbine receiver extension, the buffer in this is the standard Armalite fare.

mstennes
05-18-11, 09:11
I can't run it suppressed (therefore some over spray of paint on the brake I didn't wipe off :jester:)

I was looking for a good brake for the AR10, as with an A2 compensator there was a lot of muzzle flip. The SF brake does a good job, but nobody around me enjoys it the way I do lol.

I have Slash's buffer in another AR10 that runs an AR10 spec carbine receiver extension, the buffer in this is the standard Armalite fare.

Ok so which buffer and spring do I want to run? Most everywhere I look, either their sold out, or carbine parts. One dealer said the carbine and rifle spring are the same, and will work in both????