Need help

[cdelaney]

Ive recently acquired a new m&p10. One of the upgrades I did was replace the stock with a Magpul PRS. As such I replaced the buffer assembly with DPMS ar10 rifle length buffer, tube, and spring.

Now I am having cycling issues. 7.62 nato ammo mis-feeds every couple of rounds. higher pressure 308 rounds feed correctly but will not lock the bolt back when the magazine is empty.

I suspect the problem is in the spring but I have got zero help from the emails that smith&wesson sends me. I even asked if I could order the buffer assembly from the camo version that has the moe rifle stock on it. They told me that all their ar10's have exactly the same buffer assembly.

can anybody help with this?

 

[sgtpayne]

have you read the "short stroking" conversations? might be worth a shot to see if you having the same experiences

 

[jbowpsp]

I was reading on switching out stocks like this also (the UBR version or the fixed MOE stock). What I understand is that the 2 problems you have to watch out for is spring strength/length and buffer length/weight.

I bet that the buffer is too long. If you can pull back the charging handle and manually lock the bolt then the buffer is not too long and its prob spring or the buffer itself is too heavy for our bolt. (I am just thinking logic on this one, never experienced so double check with others). If it doesn't lock up, then you know the buffer is too long and I would just put the stock S&W carbine buffer in and try it out to check that theory.

Actually, I would use the stock one probably anyway and only change it if I had a problem.

 

[Blueapplepooh]

OP

Read this thread,

http://smith-wessonforum.com/smith-wesson-m-p10-rifles/306612-m-p-10-short-stroking.html

These rifles need to be broken in it seems. Use that bad boy.

 

[cdelaney]

I should clarify that I can lock the bolt back manually, the jams I was getting with the nato rounds was a bolt override and it was just cleaned before I took it out.

I did put almost 100 rounds through it before I changed the stock and everything was working great. I was able to put about 50 rounds through even with the problems after I changed the stock. I don't think break in is the problem.

I checked the short stroking thread but he was having problems with the gas block. I pretty sure my problem is in the spring or buffer.

Has anyone else successfully changed the buffer assembly? Which buffer spring or buffer should I look for?

 

[cdelaney]

I recently tried using some tula 150gr .308 and my rifle cycled perfectly. I think the recoil was even a little less harsh. at least the bruise on my shoulder was smaller. I know the tula has a little higher pressure then the other stuff I was using I don't know If that did it or if it was the ludicrous amounts of lube i put on the spring

while I didn't find the answer I was looking for here I did solve my problem. I figured I should share in case someone else had the same question

 

[bubster47]

I recently changed the buffer and spring in my M&P 10. I actually did it to mitigate the recoil some so my wife was more comfortable shooting it. I got the XH carbine buffer and AR10 spring from heavybuffers.com. The only ammo I've had problems with since doing that is the HSM 150 grain, but I think it may have just been a bad lot (testing new lots in a few hours).

I'm wondering if the rifle length buffer might be the problem? These come stock with a carbine, and Clint at heavybuffers.com recommended a carbine length buffer for me.

 

[cdelaney]

I'm wondering if the rifle length buffer might be the problem? These come stock with a carbine, and Clint at heavybuffers.com recommended a carbine length buffer for me.

I switched to a rifle length buffer tube. so I had to switch to the rifle length spring and buffer

 

[bubster47]

The stock setup is a rifle length tube, a rifle length spring, and a carbine length buffer. That's why I questioned the change to a rifle length buffer.

 

[jbowpsp]

The stock setup is a rifle length tube, a rifle length spring, and a carbine length buffer. That's why I questioned the change to a rifle length buffer.

That is awesome! so in the future all I have to do is buy an actual rifle buffer tube, use stock spring and buffer and I can add a fixed stock?! That is really good information to know!

 

[cdelaney]

The stock setup is a rifle length tube, a rifle length spring, and a carbine length buffer. That's why I questioned the change to a rifle length buffer.

curious, do you have the hunting/camo model? because mine came with a collapseable stock so: carbine tube, spring and buffer

 

[Blueapplepooh]

Read these threads please,

http://smith-wessonforum.com/smith-wesson-m-p10-rifles/314359-stock-options.html

M&P 10 stock options - AR15.COM

Our M&P 10's have a lot of proprietary parts in it. Released this past Jan. parts should be out this summer I'd imagine.

The second link has responses from S&W CS.

 

[bubster47]

curious, do you have the hunting/camo model? because mine came with a collapseable stock so: carbine tube, spring and buffer

No, its not the camo model, just the standard black not a compliant model. Mine also has the adjustable stock. Not sure why they would have different configurations for the same gun, kinda weird!