IRA-10D buffer damage.

[mjsemtex]

trying to get some input on this... having problems with wear on the buffer in my IRA-10D. i'm using iron ridge upper and lower receivers, a fulton armory BCG. i had originally posted some pics over on sniper's hide.

http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=2071770

i've recently found that the bolt carrier group doesn't seem to sit flush with the rear of the upper receiver, possibly the root of the problem i'm having with the excessive damage to the edge of the buffer.

any input?

[98Z5V]

Wrong rifle-length spring.  The pics you posted over there are AR-15 rifle-length springs (both).  Relaxed length matches the AR-15 spring, and AR-15 springs have 44 coils to them.  I tried to count the coils on that and came up with 40 - but it's hard to see them and count.  Regardless, it's more coils than the AR-10 rifle-length spring should have.  AR-10 rifle-length springs should have a relaxed length of 13.75" and have 34 coils to them.

Those gouges around the outer edge of the buffer - that thing is beat up pretty good.  I'd bet it's from the use of the springs in the pics, probably.  What does the end of the bolt carrier look like?

[mjsemtex]

Wrong rifle-length spring.  The pics you posted over there are AR-15 rifle-length springs (both).  Relaxed length matches the AR-15 spring, and AR-15 springs have 44 coils to them.  I tried to count the coils on that and came up with 40 - but it's hard to see them and count.  Regardless, it's more coils than the AR-10 rifle-length spring should have.  AR-10 rifle-length springs should have a relaxed length of 13.75" and have 34 coils to them.

Those gouges around the outer edge of the buffer - that thing is beat up pretty good.  I'd bet it's from the use of the springs in the pics, probably.  What does the end of the bolt carrier look like?

the bolt carrier isn't showing wear... just the marks around the edges of the buffer so far.

[mjsemtex]

so, i've not only been supplied with the wrong buffer spring when i originally purchased the complete lower from iron ridge but, i've also been sold the wrong buffer spring from midwayusa when i ordered the replacement.

[98Z5V]

Do you have a known AR-15 rifle length spring to compare the two you have against?

I pulled my Fulton AR-10 rifle spring out and compared it to a known AR-15 rifle spring just now.  My Fulton spring has 37 coils to it, and it's 3/4" longer than my AR-15 spring.  Both are used (well used), and don't meet the relaxed length criteria.  There's a definite difference on the 10 spring over the 15 spring, though.  Spacing of coils, number of coils, length, stiffness...  The 10 spring is much, much stronger than the 15 spring.

[mjsemtex]

that's definitely something i can compare when i'm home later this afternoon.

wouldn't the 'stronger' spring cause even more damage to the buffer as it seems to slam into the retainer pin?

some of my concern also lies in the fact that the BCG isn't flush with the back of the upper as it is in all of my AR-15s... it would seem that instead of the buffer slamming home against the carrier group, the retainer is taking the brunt of the force. when i close the upper down onto the lower, there does seem to be a gap between the buffer and the rear of the BCG.

[survivalshop]

I would like to see photos of the BCG in the upper receiver .

The marks on the buffer are from the buffer stop . I would look closely at the stops hole in the lower receiver & see if its getting beat up .

By the time the buffer gets to the point where it is stopped by the buffer stop , it should have slowed down considerably, because the bolt is cam-ing into lock position .

The forward motion of the buffer from the wrong spring ( & inertia of the buffer its self)may be to fast & hard.

[mjsemtex]

wouldn't the 'stronger' spring cause even more damage to the buffer as it seems to slam into the retainer pin?

[98Z5V]

wouldn't the 'stronger' spring cause even more damage to the buffer as it seems to slam into the retainer pin?

Depends.  I'm not completely sure what's happening with your rifle, but this might be a possibility:  softer spring isn't eating the force and weight of the BCG coming back after firing.  Everything is slamming into the end of the receiver extension, then rebounding forward even harder.  Check the condition of the little poly bumper on the end of the buffer; see if it's split or cracked anywhere.

I've never seen a buffer chewed up like that, so this is all guesswork on my part.  The marks have to be coming from the buffer retaining pin, that's a given.  The "why" though, I'm trying to figure out myself.  The AR-10 spring is one strong, stiff spring.  It's not doing that to my buffer.  There are lots of guys running that spring, and it doesn't chew up the edges of the buffer.  That much I know.  Something is causing this, and people here will try to help figure it out - getting a comparison of your rifle spring against a known AR-15 rifle spring will help greatly.  <thumbsup>

[survivalshop]

First off ,I'm no spring expert, but I know the wrong spring for the application opens up a lot of problems .

Being stronger  , may be only at its full or close to full compression , in this case . How it compresses & releases is engineered into them .

What type stock are you running , full rifle or collapsible ?

I also find it strange that the wrong spring was installed & also shipped to you .

From the photos of the springs and if I'm counting right , it looks like 36 coils on the one & 34 on the other , but I may be counting them wrong.(every time I count them ,I get different counts :P )

Also is you receiver extention ,on correctly. Looks like the buffer could be skipping over the buffer retaining pin .

As said ,I would like to see a photo of the BCG in the upper receiver ,that you say doesn't look right.

[imschur]

Can you take some better pictures? Is the buffer retainer at the correct depth?

[98Z5V]

OP, O saw that you mentioned this over on SH:

also, i had used this complete lower receiver with a DPMS-mfg upper receiver previous to the availability of the IRA uppers and did not experience any of these wear issues.

Still have the DPMS upper that was on this IRA lower?  Maybe it is the fact that the carrier is too far inside the upper receiver.  There's a small $50 work-around that might fix this, if that's the case.

Tubb Carrier Weight System.  Sticks into the back of the carrier.  That might be the additional length you'd need to close the gap between the carrier and the buffer.  <thumbsup>

A quote from the part description:

CWS™ also incorporates a flange that serves to secure it in the bolt carrier, but this also significantly reduces carrier overrun past the bolt stop. Reducing the distance the carrier must return to engage the bolt stop extends the life of this part and further reduces the amount of rifle movement apparent to the shooter. This is of special help to the AR-10/SR-25 owner since these rifles are notorious for breaking bolt stops.

More info on the product here:

http://www.davidtubb.com/ar15_cws.html

[otango]

HI

Iron Ridge Will need to see the whole firearm, so we can determine  what the problem is.

who set up the rifle ? what type of action spring is being used. Etc. you will have a gap between the carrier and Buffer. But hard to work it out on line/ give us a call or email us your phone number and we can figure this out,  never had this issue with other builds.

thx.

Tech@IronRidgeGuns.com

[imschur]

mjsemtex let us know how you make out.

Thanks otango  <thumbsup>

[survivalshop]

Any updates ? Inquiring minds want to know .

[SWshooter]

I just examined my lr-308 closely and my BCG pushes the buffer off the stop when the receiver is closed. The buffer stop is there only to retain the buffer and spring when the receiver is open. The buffer shouldn't touch the buffer stop when firing the rifle. This seems to indicate that the upper receiver and BCG are incompatible on your rifle.

[survivalshop]

I just examined my lr-308 closely and my BCG pushes the buffer off the stop when the receiver is closed. The buffer stop is there only to retain the buffer and spring when the receiver is open. The buffer shouldn't touch the buffer stop when firing the rifle. This seems to indicate that the upper receiver and BCG are incompatible on your rifle.

That's correct.

Hows the head space?

[metalmole]

I have seen this very damage on both 556 and 762 rifles, caused by the buffer retainer machined in the wrong place!  As one of you stated that when closing your action the carrier tail pushed the buffer off the retainer pin, that's what should happen. If the retainer pin is in the wrong place ( machined too far to the rear ) it will eat up the buffer, most of the time the pin will break..................

[survivalshop]

I have seen this very damage on both 556 and 762 rifles, caused by the buffer retainer machined in the wrong place!  As one of you stated that when closing your action the carrier tail pushed the buffer off the retainer pin, that's what should happen. If the retainer pin is in the wrong place ( machined too far to the rear ) it will eat up the buffer, most of the time the pin will break..................

Now  that makes sense , an out of spec lower . Send it to the manufacturer.( as they ,Iron ridge , pointed out , by the way.)

[mjsemtex]

Any updates ? Inquiring minds want to know .

currently on its way back to iron ridge.

[mjsemtex]

waiting on the completion of IRA's GEN 2 upper...

[mjsemtex]

iron ridge has had the rifle / parts since early december and had said that they were going to replace the upper with their 'gen 2'... but, had also said that this wouldn't solve the way it was banging up the buffer as that was 'normal' in all AR rifles.

as i was unhappy with this response, they've offered to refund my purchases from them. which i accepted.

now, i'm waiting on the refund... i'd have thought it would be immediate which is not the case.

[survivalshop]

iron ridge has had the rifle / parts since early december and had said that they were going to replace the upper with their 'gen 2'... but, had also said that this wouldn't solve the way it was banging up the buffer as that was 'normal' in all AR rifles.as i was unhappy with this response, they've offered to refund my purchases from them. which i accepted.

now, i'm waiting on the refund... i'd have thought it would be immediate which is not the case.

The only place I have seen that kind of damage is on the internet forums & yours is the second one .

That is NOT normal .

[mjsemtex]

The only place I have seen that kind of damage is on the internet forums & yours is the second one .

That is NOT normal .

i agree completely.

and, if offered a refund, i'd assume it would be an immediate solution. i'm still waiting with no definite answer.

[98Z5V]

The only place I have seen that kind of damage is on the internet forums & yours is the second one .

That is NOT normal .

Exact same opinion - only seen it twice, and never, ever in person, on any AR in any caliber.  That ain't right, no matter how they try to sugarcoat it.  >:(