New member from Virginia - AR10 chambering issue?

[Mike703]

Hi everyone! Mike here from Virginia. New to the site but not to AR's.

So I built a 12.5" AR10 pistol on a Spikes Jack10 receiver set. It wont cycle and is hard to chamber. Ejects fine but will not cycle the next round. Same results using DPMS 10 & 20 round mags and Magpul 20&25 round mags. The bolt doesn't seem to come back far enough to grab the next round. Using a PSA PA-10 buffer and spring so I'm guessing that the buffer tube or buffer length is the issue. I saw another thread on here with the same issue but it was supposedly the wrong buffer spring but I don't think that's my problem here.

Any ideas?

[shepp]

Get the guys messurements someone will help, spring/buffer/ tube depth also count the coils on your spring. Lubed well? Like wet wet well? 

 

Welcome to the forum from Wisconsin nice Looking pistola you got there

[98Z5V]

If it's the PSA PA-10 carbine receiver extension, I just recently got hands-on with one of those - they have an unusually long internal depth to them.  A little longer than AR-10-length, which is 7 5/8".  They're not machined toany kind of a standard,and PSA ships them with the wrong buffer (DPMS LR-308 based buffer, at 2.5").

I'd shitcan your recoil system and get known good parts, honestly.  Measure out what you have now, and get pics up, but be ready to find out some weird information...

[Matt.Cross]

Based on what you've described, your issue sounds like the buffer length. Which is luckily easily fixed, if you are capable of using a drill and a hacksaw.

Pull the charging handle and hold it as far to the rear as you possibly can, then manually engage the bolt release to catch the bolt. If the bolt catch doesn't hold the bolt to the rear when you release the charging handle, your buffer is probably too long.

[AnOldBiker]

Welcome to the forum

[unforgiven]

Welcome from Indiana brother interesting setup.

[Mike703]

So it was the buffer spring after all.

The PSA AR10 buffer spring was too long and bottomed out too soon limiting the rearward travel distance of the bolt. BOOM BOOM BOOM! 

[unforgiven]

It seems like it's the Armalite recoil system for the win in the majority of the cases. It worked for me. Just my 2 mags

[Malig8r]

Welcome to the forum. Lots of good knowledge here.

[Mike703]

Thanks Malig8r. Apparently good dog owners here too. Here's our Maligator Eva. 

[Armed Eye Doc]

She's a beautiful pup.

[unforgiven]

A bueaty for sure 

[Mike703]

Yeah, that's her I want to shred another ATV tire into pieces face. Lol. 

[washguy]

1 hour ago, unforgiven said:

A bueaty for sure 

Daaamn great lookin pup !     Makes me miss my GS ..       Wash

[jtallen83]

Welcome from Iowa, via Mississippi!

[Rsquared]

Welcome from Maryland.

[GoodByNAair]

Welcome from the gun loving state of Maryland....

[Mike703]

Thanks MArylanders. Good to be on the Virginia side of the river. 

[Rsquared]

On ‎4‎/‎26‎/‎2018 at 9:45 PM, Mike703 said:

Thanks MArylanders. Good to be on the Virginia side of the river. 

I wouldn't go that far dude. You've still got ALL of the "Very Liberal" northern Virginian's that seem to run that state. Though granted, you all aren't as communist as this state..........yet. Just give it time. Anything that even touches DC is slowly rotted as the cancer spreads.

[98Z5V]

I's still like to see the specs on the rest of this carbine recoil system, to not overlook anything else.  It's usually not just a buffer spring that can cause this kind of issue...

That data was never provided.

Using a PSA PA-10 buffer and spring so I'm guessing that the buffer tube or buffer length is the issue.

Just the PSA buffer and spring.  That fancy receiver extension isn't PSA - I've never seen anything like it. Specs on it is just about mandatory.

Measure out what you have now, and get pics up, but be ready to find out some weird information...

Zero received, in this regard. Buffer length and weight, receiver extension internal depth, spring relaxed length, coil count, and possible wire diameter.

That info is the only way to assess whether your recoil system is up to the task of .308 Win ammo...

Or, whatever.

Edited April 28, 2018 by 98Z5V

[Mike703]

23 minutes ago, 98Z5V said:

98z5v

Good observation. The receiver extension is a KAK peanut. It’s 7.10” internal depth and not 7.375”. 

I ordered this generic AR10 pistol kit (link below) just to compare it to what I had. The .308 receiver extension I received was also 7.10 internal depth. The 3.8 oz buffer was the same length at 2.5” only difference was the spring was slightly shorter and bottomed out at about .25”-.275” shorter than the PSA spring allowing the bolt to come back far enough. 

https://otsupplier.com/Mil-Spec-Pistol-Buffer-Tube-Kit-AR-10

I didn’t count the coils or measure wire diameter but the bolt finally came back far enough for the bolt catch to function. Shot fine with DPMS mags and Pmags. 

Next time I have it out I’ll get more specs for you.

 

 

23 minutes ago, 98Z5V said:

I's still like to see the specs on the rest of this carbine recoil system, to not overlook anything else.  It's usually not just a buffer spring that can cause this kind of issue...

That data was never provided.

 

 

Just the PSA buffer and spring.  That fancy receiver extension isn't PSA - I've never seen anything like it. Specs on it is just about mandatory.

 

 

Zero received, in this regard. Buffer length and weight, receiver extension internal depth, spring relaxed length, coil count, and possible wire diameter.

That info is the only way to assess whether your recoil system is up to the task of .308 Win ammo...

Or, whatever.

 

[98Z5V]

I've had a7.100" internal depth receiver extension cause functional issues in 308 ARs.  The spec is 7.000" internal depth, based off the AR-15 carbine receiver extension, not longer.  So, there's that.

The 3.8oz buffer is light for a 308AR. That's AR15 carbine buffer weight, right there. The length is good, if it's a true 2.500".

Just information for you. 

With this combination, you should probably run a heavier 2.500" buffer (around AR15 Carbine H3 weight), and the Sprinco orange spring, and stack one quarter in the receiver extension - if you're stuck on keeping that receiver extension. Stacking two would bring you under the 7.000" internal depth that would make a proper, functioning recoil system for a 308 AR...

I could have given all this information out, had I known the specs previously...

[98Z5V]

12 minutes ago, Mike703 said:

The receiver extension is a KAK peanut. It’s 7.10” internal depth and not 7.375”. 

 

I'm not aware of any aftermarket receiver extensions in a 7.375" internal depth, for anything out there.  That would be 7 3/8".

Edited April 28, 2018 by 98Z5V

[Mike703]

1 hour ago, Rsquared said:

I wouldn't go that far dude. You've still got ALL of the "Very Liberal" northern Virginian's that seem to run that state. Though granted, you all aren't as communist as this state..........yet. Just give it time. Anything that even touches DC is slowly rotted as the cancer spreads.

Rsquared, I am working on these “Very Liberals” here. And I vote.

In 4 years I got 6 Boy Scout dads to get their sons there first .22 rifle and got 8 Boy Scouts qualified with their NRA range safety passes. 

If more Northern Virginians advocated like me we might have a chance to keep from becoming like CommAryland. 

[Mike703]

8 minutes ago, 98Z5V said:

I'm not aware of any aftermarket receiver extensions in a 7.375" internal depth, for anything out there.  That would be 7 3/8".

Oops 7.675” (PSA receiver extensions)

thanks for the info!