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Buffers and Springs

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Do not use AR-15 buffers and springs in a 308 AR. These parts are 308 specific.

Either use what your rifle manufacturer would supply or visit heavybuffers.com for aftermarket buffers and technical info.

Click here for Buffer Springs

Click here for Tubb Superior Shooting Systems Flat Wound Springs

Click here for 308 Buffers

Click here for the Endine AR Restor


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First, as was stated previously, ALL buffer tube have the same inside diameter. Only the outside diameter is different. Buffer selection is dependent on the length of the tube (and the type of gun), not the diameter.

Carbine buffer tubes (receiver extensions) are available in two different lengths.  A standard AR15 type tube is 7" long inside and an AR10 (VLTOR) tube is 7-3/4" long inside. 

All carbine buffers ARE NOT the same length!  There are three basic variations. 

1 - AR15 buffers are 3.250" long and will work (obviously) in any AR15 with a standard carbine buffer tube.  These same buffers will also work on ArmaLite and DPMS pattern .308 ARs if you use the extended buffer tube. 

2 - .308 carbine buffers are shorter and will allow you to use an AR15 type buffer tube on a .308 AR.  A modified .308 spring is sometimes required for proper function.

3 - Rock River Arms require an even shorter buffer and a modified spring.

It is important to note that you should never use a buffer that is shorter than required for your specific application.  You most definitely CAN pick a buffer that it too short. IE - A RRA .308 carbine buffer will physically fit into any other configuration.  But if you were to install one of these buffers into say, an AR10 with an AR15 tube, the bolt will over-travel and the carrier key will strike the lower receiver ring and mayhem will ensue.

Is is important to make sure that you use a .308 buffer spring in ALL .308 ARs.  NEVER use ANY AR15 buffer spring in a .308 AR.  I strongly recommend using ArmaLite AR10 buffer springs, and I discourage the use of any 'Flat Wire' spring.

The difference between a "$100 buffer" and the DPMS .308 carbine buffers is MASS.  The DPMS buffers weigh only about 1/3 oz. more than and AR15 carbine buffer. Way too light when you consider the differences in pressure between .223 and .308. DPMS merely took a shortcut, there's a reason why they don't offer a lifetime warranty.  Their buffer is simply an H3 buffer that is cut down in length and then they remove one of the Tungsten weights.  A great 'field expedient' method, but not good for your gun in the long term.  A lot of customers turn to me when their DPMS factory carbines start breaking parts. I strongly discourage using any buffer lighter than an H3 in a .308 AR.

Final note - You can't 'upgrade' a factory DPMS carbine to an H3 buffer unless you also upgrade to an ArmaLite/VLTOR buffer tube.  The DPMS tube is too short and will restrict bolt travel.  The gun will not eject/chamber a round from the magazine.

I hope that this information is helpful.  If any questions remain please feel free to contact me.

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The CAR-10 buffer will allow you to use any AR15 collapsing stock (MagPul/LMT/VLTOR/CavArms/etc) on your AR10, SR25, LMT, POF or DPMS-pattern .308 rifle.

This product is specifically recommended by Magpul for use with their UBR stock on .308 ARs.  CAR-10 buffers work great with any other  stock using a standard 7" carbine buffer tube.

CAR-10 buffers are shorter and heavier than standard carbine buffers. Constructed of 303 Stainless Steel with a sliding Tungsten anti-bounce counterweight. Heavy buffers reduce felt recoil for the shooter, and minimize wear and tear on the gun. Some users have reported that the CAR-10 buffer significantly increased the reliability of their firearms.

This is strictly a 'Drop-In' part, no gunsmithing or modifications are required. I recommend using modified ArmaLite AR10 rifle buffer springs with these buffers. OEM springs from other manufacturers or aftermarket springs may cause malfunctions. 'Flat-Wire' springs are not recommended.

Note: This buffer is designed for use in .308 ARs with a 7" receiver extension (buffer tube). If you have an ArmaLite/VLTOR extended length tube (7-3/4") please see the AR15 Carbine Buffer page. Not compatible with .223 ARs.

CAR-10 Buffer & Modified Buffer Spring - $111 plus shipping.

CAR-10 XH Buffer & Modified Buffer Spring - $137 plus shipping

Extra-Heavy model for suppressed weapons, or for maximum recoil reduction in non-suppressed guns.


Recommended for use with suppressed weapons. Also a great option  to help reduce recoil in non-suppressed guns. Works great with the popular "Big-Bore" calibers - 450 Bushmaster, .458 SOCOM, .50 Beowulf and others. Some customers are using this buffer in standard .308 ARs to make shooting more comfortable for their youngsters.

I strongly recommend this buffer if any of the following conditions apply:

  • If you will be shooting with a suppressor. (Your gun will still run fine unsuppressed with standard ammunition.)
  • If you will be shooting hot handloads or very heavy bullets.
  • If you want maximum recoil reduction.

I recommend using ArmaLite AR10 rifle buffer springs with these buffers. OEM springs from other manufacturers or aftermarket springs may cause malfunctions. 'Flat-Wire' springs are not recommended.

AR10R-XH Buffer & Spring - $137 plus shipping.

More info http://www.heavybuffers.com

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