300 Blackout & Vltor's A5 system?

[gabuzz12]

I just purchased a DDM4V5 300 blackout 16" rifle and I'm considering installing vltor's a5 buffer system on the rifle because of the success I've seen with my 5.56 16" rifle, which also has the a5 installed. I'm mainly concerned about its ability to.shoot suppressed especially after higher round counts. Any thought on the performance of the rifle with the a5 and if the a5 is a good solution for this setup? Thanks in advance guys

[Iraqgunz]

All I can say is that I fired my .300 BLK upper for the first time last week (10" Noveske barrel) on an A5 lower with the H3 buffer and green Springco spring. I was shooting the Remington 125gr. supersonic and it was smooth like a baby's ass.

I think you will be fine. I would encourage you to look at a Springco spring as they truly seem to last longer than standard springs.

[BC98]

I run an A5 system with a 9" 300 BLK barrel and it seems to be working just fine. It's ran with with factory Remington 115gr and 125gr loads, factory 220gr subs, and all of my handloads (including some weak subsonic loads). All rounds were shot unsuppressed as MN is not suppressor-friendly. All rounds cycled and the bolt locked open on the last shot.

I'm currently using the stock A5 buffer and VLTOR spring but will be experimenting with other buffer weights and springs, as IG suggested, to see how felt recoil changes. Since this lower shares time with a short 5.56 upper, I'm also making sure that it runs well with that setup.

[Clint]

As has been stated in numerous threads, the A5 system is probably the most consistent and forgiving buffer system available.

The other day I ran IMI 5.56 and MFS steel case through a 16" BCM middy upper all with perfect function and 3-4 O'Clock ejection.

Then I switched the upper out for an ARP 6.8 16" middy upper and ran 110gr and 120gr loads, again with perfect function.

Since you already have an A5 lower, your "cost to try" is zero.

I'd say try it out with the 300 and it will most likely work fine.

[gabuzz12]

Thanks guys. I failed to mention that I also plan to install the green Springco spring as well. Sounds like it will be just fine. Thanks again for the info guys

[Todd.K]

As a general rule I've found gas ports designed to function with an H2 buffer and carbine spring do well with a rifle (or A5) buffer and rifle spring.

Your carbine gas 300 BLK is probably designed for a carbine or H buffer with subsonic. The A5 will probably do well with supersonic and may with subs suppressed, but is probably not optimal for subs unsuppressed.

The shorter 300 BLK barrels (like ours) are often designed for H2 buffers, they run well with an A5.

[scottryan]

As a general rule I've found gas ports designed to function with an H2 buffer and carbine spring do well with a rifle (or A5) buffer and rifle spring.

Your carbine gas 300 BLK is probably designed for a carbine or H buffer with subsonic. The A5 will probably do well with supersonic and may with subs suppressed, but is probably not optimal for subs unsuppressed.

The shorter 300 BLK barrels (like ours) are often designed for H2 buffers, they run well with an A5.

I don't know how that works. I have to use a car weight buffer and colt usgi spring to get my 10" noveske barrel to work with 220gr remington.

[Todd.K]

Unsuppressed?

[scottryan]

Unsuppressed?

1. The gun will run 100% flawless with a 3.0 oz Colt CAR buffer, Colt carbine spring, with 220gr Remington factory loads either suppressed or unsuppressed. It doesn't matter if the silencer is attached. I have been using an AAC N6 with a 3 prong. This is with a standard Colt full auto bolt carrier group.

2. With an H buffer and the same setup, it will not lock back about 10% of the time either suppressed or unsuppressed.

3. With an H2 buffer the failure rate is more.

The barrel is the first run of Noveske .300 blk 10" barrels with 1/8 twist. I have been extensively testing this setup to find out where it will be 100% reliable and it is the configuration in #1.

[Clint]

...on an A5 lower with the H3 buffer and green Springco spring...I would encourage you to look at a Springco spring as they truly seem to last longer than standard springs.

Is the green spring a "standard strength" rifle spring or "extra power"?

The A5 tube being slightly shorter than the rifle tube, already has ~10% higher force using the same spring.

I don't think too much more spring power would be desirable with the A5.