AR-10 (Smith & Wesson) short stroking

Realtor · Jun 28, 2018

No, I just allowed the round to come from the mag, its a Pmag. My neighbor has a scale, we just weighed the buffer, its 2.985 OZ. Just for kicks we weighed the buffer from the M&P 223. It weighed the exact same (2.985), however the spring was shorter in the 223. so this leads me to thinking I either need a heavier buffer (5.4 OZ) or a lighter shorter spring. My 308 spring is 13 inches, and I see the standard 308 spring is 12 3/4...
I can't imagine, S&W put the incorrect buffer in this?

John B. · Jun 28, 2018

I think you may be overthinking an undergassed issue. Is the gas block properly aligned?

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Jester896 · Jun 28, 2018

Did you try the .223 spring?
Can you lock the bolt back?
Are there scratches on the case like there may be some extra finish in the chamber?

Telum Pisces · Jun 28, 2018

If lubed and good ammo does not work on a new gun I'd be sending it back

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Realtor · Jun 28, 2018

Realtor said:
No, I just allowed the round to come from the mag, its a Pmag. My neighbor has a scale, we just weighed the buffer, its 2.985 OZ. Just for kicks we weighed the buffer from the M&P 223. It weighed the exact same (2.985), however the spring was shorter in the 223. so this leads me to thinking I either need a heavier buffer (5.4 OZ) or a lighter shorter spring. My 308 spring is 13 inches, and I see the standard 308 spring is 12 3/4...
I can't imagine, S&W put the incorrect buffer in this?

John B. said:
I think you may be overthinking an undergassed issue. Is the gas block properly aligned?

Sent from my SM-G950U using Tapatalk

Yes, no obstructions anywhere

Jester896 said:
Did you try the .223 spring?
Can you lock the bolt back?
Are there scratches on the case like there may be some extra finish in the chamber?

NO, I sis not try the 223 spring. its smaller than what's in the 308, didn't want to bottom it out and damage anything. yes, the bolt locks back manually with an empty mag. yes, and no strange marks on the spent cases.

if the springs don't correct the issue, she's going back to s&w...

John B. · Jun 28, 2018

I agree, it needs to go back to SW before you start swapping parts.

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Realtor · Jun 28, 2018

at this point 50 bucks for a buffer and spring is worth trying. 4-6 week turn around when you send it in, if I'm lucky....

SGB · Jun 28, 2018

Have you checked the gas key too insure it's staked properly and not loose?
Do the fired cases have a dull "frosty" look to them?
Does the extractor ever slip off the rim of the case during extraction?

RumbleWepnz · Jun 29, 2018

Realtor,

Use the Brownell's Modified 308AR buffer spring, part # 100-007-354. It should solve your problem. Leave the buffer alone, it is correct and will work with the new spring.

Good luck.

FrommerStop · Jun 29, 2018

John B. said:
I think you may be overthinking an undergassed issue. Is the gas block properly aligned?

Sent from my SM-G950U using Tapatalk

My thought also undergassed for some reason. Or there is s serious mechanical issue. Use NATO spec 150 grain loads that the gun was likely designed around. If the gun is undergassed or mechanically wrong send it back to get fixed. Does not sound like you want lighten the spring or fool with the buffer since it is already less than 3 oz.
The most important thing prior to sending it is back is too make sure you use the precise ammo type recommended in your owners manual.

Realtor · Jun 29, 2018

SGB said:
Have you checked the gas key too insure it's staked properly and not loose?
Do the fired cases have a dull "frosty" look to them?
Does the extractor ever slip off the rim of the case during extraction?

the cases come out looking just like they did when they went in. less the internals...

RumbleWepnz said:
Realtor,

Use the Brownell's Modified 308AR buffer spring, part # 100-007-354. It should solve your problem. Leave the buffer alone, it is correct and will work with the new spring.

Good luck.

I already ordered the PA stuff, if that doesn't do it, It's getting sent back to S&W. I'm pretty disappointed in S&W right now. The other gins I have from them has been great, they work the same every time....

FrommerStop said:
My thought also undergassed for some reason. Or there is s serious mechanical issue. Use NATO spec 150 grain loads that the gun was likely designed around. If the gun is undergassed or mechanically wrong send it back to get fixed. Does not sound like you want lighten the spring or fool with the buffer since it is already less than 3 oz.
The most important thing prior to sending it is back is too make sure you use the precise ammo type recommended in your owners manual.

yes, there is a problem, it wont completely cycle brass. so I've used 150 gr 168 gr 308 win. that's what it states to use. Its close to being sent back......

FrommerStop · Jun 29, 2018

Realtor said:
the cases come out looking just like they did when they went in. less the internals...

I already ordered the PA stuff, if that doesn't do it, It's getting sent back to S&W. I'm pretty disappointed in S&W right now. The other gins I have from them has been great, they work the same every time....

yes, there is a problem, it wont completely cycle brass. so I've used 150 gr 168 gr 308 win. that's what it states to use. Its close to being sent back......

I understand the disappointment. So often brand new guns are not right. Means the manufacturer did not bother to at least function fire the gun. For what you paid for it I am sure that should have been included. I would want to see a target and the empty fired cases. Never is done.

Realtor · Jul 3, 2018

new spring, new heavy buffer did nothing, this thing is headed back to Smith and Wesson for them to figure it out.... Thanks for the suggestions and all, but this just IS NOT right. It's going back....

strange, same as before, could not even tell I did anything....

Again, Thanks for the efforts of the forum, It's time for this to take a trip...

John B. · Jul 3, 2018

Undergassed.

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Realtor · Jul 3, 2018

John B. said:
Undergassed.

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has to be..... they'll figure it out at this point.....

Roaster's Gallery · Jul 3, 2018

I don't think a heavier buffer was the right decision. I would have tried a lighter buffer.

John B. · Jul 3, 2018

Realtor said:
has to be..... they'll figure it out at this point.....

Unfortunately, the way the industry is, S&W has had to adapt, and get in to the market of building budget rifles. They make phenomenal wheel guns, but how many of us have a 30yr old revolver that still works fine? I do. Kind of hard to stay in business without selling new guns... enter the budget ar-10/ar-15...

Send it back. The wait will suck but they will make it right.

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SAWMAN · Jul 3, 2018

Too bad you didn't pick up that DPMS for sale here. ---- SAWMAN

Realtor · Jul 3, 2018

SAWMAN said:
Too bad you didn't pick up that DPMS for sale here. ---- SAWMAN

I did...… :smile: it shot just fine this morning. I was hitting clay pigeons (not in the air lol ) at 125 yards... I mixed in Brass and steel case ammo in the same mag, and the gun didn't even burp... lol I don't think it knew...

The S&W is still going back.... I'm sure they will fix it, but I just wanted it to be right out of the box....

SAWMAN · Jul 3, 2018

Congratz on that new gun. My DPMS Panther Arms runs with all my reloads. From light loaded 110's to heavy loaded 220's. So far . . . no adjustable gas block needed.
My guns favorite are the Sierra 155gr Palma's. ---- SAWMAN

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AR-10 (Smith & Wesson) short stroking

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