H. H2, H3 or 9mm buffer?

AR/M4 AR Technical Discussion
1

Hello folks,

I will appreciate your thoughts about wich buffer to use in the following setup:

WOA 18" SPR Bbl with Rifle gas system
Semi automatic BCG
ISMI Carbine Spring.

I know the added buffer weight enhances cycling armony in carbine gas systems, but what about rifle gas systems?

Thanks.

2

First off, 18" barrels with rifle length gas systems are somewhat finicky (especially in cold weather). This is why all current .Mil SPR’s have middy gas systems.

Since you are running an ISMI spring, I would most likely go with a carbine buffer as the rifle length gas system is so mild.

C4

3

use a lighter buffer but test out the function with underpowered ammo, cold weather etc… know your weapon and now its limits…

rifle 5.2oz
car 2.9oz
9mm 5.5oz
h 3.8oz

I’d look into car buffer and H buffers :slight_smile:

4

My MK 12 MOD1 type SPR was very sensitive to different ammo and cold weather. I thought it was something I did wrong when I built the upper.
I ended trying every buffer out there including the enidines and MGI’s. What I found out was that the regular carbine buffer with a carbine buffer spring worked the best. I would fire wolf ammo without issues after keeping with that. I think the added weight of the Les Baer bolt carrier didnt help with the rifle length gas system.
As long as I used good ammo such as Black Hills or Hornady I could get away with the H2 buffer.
Hope this helps.

5

keep in mind issue SPR’s have a A1 stock assembly

6

If using a carbine stock I’d go with a standard 2.9oz CAR buffer and a standard rate CAR spring (rifle gas systems don’t need help, they already run lower gas pressures). With heavier buffers/springs a rifle gas length AR may become very finicky with weaker or heavier loads and/or cold temperatures. The ISMI is a stronger rate and not needed in this application and I wouldn’t use it.

For SPR clone type builds I use 18" barrels with midlength gas with CAR buffer w/standard spring unsuppressed and an H buffer w/standard spring when running a suppressor both with M16 carriers, but shrouded AR carriers work well too.

7

I agree with everything you say. All of my informal testing proves your statements to be right on.
If I build another SPR based rifle , it will have a mid length gas system.

8

Gentlemen, thanks for the replies. If I ever build an SPR again, it will be a 18" middy.

I already buit this rifle about a year ago but with an A2 stock. Not a single FTF or any ejection issues since round #1. My only complaint is that the LOP of the A2 stock its a little long for me.

So, as soon as the new Magpul UBR hits the market I’ll try one in this rifle. I was looking forward to use an ISMI spring already have as spare, but it probably remain in the spare parts box.

9

Anyone have suggestions on buffers for regular midlengths with telestocks?

I’d been running an older Enidine in mine, and it was reliable but manually locking back the bolt was a pain in the ass. I tossed a regular buffer in there a while back to see how it shot, and I really liked it. However, shooting with the can on seems to generate a bit more cycling oomph than I probably need.

10

I use CAR buffer with midlengths.

11

I’ve been using an enidine for awhile now and really like them. Same issue when I first put it in with manual lock back but for some reason that is no longer a problem. 89.00 for it aint too bad from PKFirearms either. Other people have them and are over 100.00dollars.