AR-15 Buffer Question

[BSA1]

Well actually two questions.

My AR has a 16" barrel with mid-length gas system. I built it using Bravo Company carbine buffer tube, spring and buffer.

I have not have the rifle to the range yet so it is sitting on the wall unfired. Most (95%+) of the ammunition will be my reloads using 55 gr. FMJ bullet.

Since completing the rifle and reading about overgassing and weight of buffers I wonder if I should replace the carbine buffer with a H Buffer?

The follow-up question is if I do go with a H Buffer is any brand preferred over the other?

I did a search on THR but all of the posts were several years old.

 

[badkarmamib]

My gun runs fine with the same barrel configuration, with a carbine buffer. Perfect ejection. I would try it as-is, before changing anything.

 

[chicharrones]

Same with my mid-length gas ArmaLite with standard carbine buffer. It ran great.

Now it wears a rifle extension, buffer, and stock, but it ran great with the original configuration.

 

[azrocks]

My gun runs fine with the same barrel configuration, with a carbine buffer. Perfect ejection. I would try it as-is, before changing anything.

What he said. And same here.

You never stated the make of your upper, but I"m fairly certain Bravo Company recommends carbine-weight buffers w/ their mid-length 16" barrels.

 

[wally]

Don't consider doing anything until after you've actually shot it with a variety of ammo. If it ain't broke, don't fix it!

 

[MistWolf]

My PSA middy ran good with a carbine weight buffer, but it ran even better with an H buffer. Was easier on the springs, too.

Civilian Colt carbines ship with an H buffer and they shoot real good.

Trying an H or H2 buffer won't hurt a thing except what it costs you to buy them. If your AR locks back on an empty mag with an H or H2, run it. It'll give you a little less wear & tear

 

[ClemY]

I have a couple of 16" mid length guns. I find I prefer the 5.6 oz. or 6.4 oz. buffer in mine.

 

[BSA1]

Thank you for the feedback. As a reloader I can download my ammunition for it.

MistWolf,

Do you have a preference on H Buffers?

 

[Varminterror]

What does your brass look like today? Any case head swipe or extractor damage? Where are your cases ejecting (if your port is 3 o'clock and your muzzle is 12 o'clock)?

You'll likely have folks come in and tell you to convert to a 20" barrel with rifle gas and an H2 or H3 buffer so you have the same gas pressure and same buffer weight (of course, you have to have an M16/full auto style BCG too), but frankly, all of them work.

As long as you don't have over-gassing symptoms showing up in your brass, you don't need to change anything at all. If you DO have issues, then an adjustable gas block and/or a heavier buffer and/or an extra power spring will solve your problem. I prefer an adjustable gas block over the other parts as a first measure.

That said, I do run H2 buffers in all of my carbines NOT used for 3 Gun where I want the faster cycle. I like the H2's for the reduced cycle rate and increased battery time. Not necessary though.

 

[BSA1]

I will be visiting the range later this year with it. I have too many irons in the moment including finding time to reload some .223. The nice thing about reloading is I can start with mid-range and vary the amount of powder as necessary.

 

[ny32182]

You aren't going to be able to really "download" a .223 all that much and still have it run a gas gun very reliably. My goal would just be to have a full power or very close to full power load, and set up the gun to run correctly with that.

When I got my BCM midlength, they recommended a standard (non H) carbine buffer, and mine has run fine in that configuration. You could call and confirm that is still valid.

 

[MistWolf]

Yes, I prefer the H or H2 buffer for a general purpose AR. With an H or H2 buffer, the AR has the baseline mass which gives the best functioning under the widest variety of conditions and ammo type. This also assumes the barrel has the correct port diameter and the proper action spring.

An AR can be tuned to run with less reciprocating mass (lighter buffer and/or lighter BCG) which results in less mass bouncing around to push the rifle off target during the operating cycle, but with a narrower set of operating parameters. Again, the barrel has the right size gas port.

It's also the Easy Button for a neophyte just learning how to tune an AR. Starting off with the standard setup (H/H2 buffer, carbine spring .063 diameter gas port, carbine length gas system) gives the tuner a good baseline to start from because the tuner can now change one thing at a time and see how it affects function, felt recoil and so on. Starting off with a lighter buffer means you're already stating off with a change. On top of that, ARs equipped with carbine buffers often come with gas ports that are too large. Now, you have two deviations from the norm. Finally, when it's all said and done, the tuner is going to end up running an H/H2 buffer and tossing the carbine buffer in the parts bin.

If you really want an education in AR tuning, get barrel with an oversized gas port and install an SLR adjustable gas port. Adjust the block until the rifle just locks back on an empty mag, then adjust it until the rifle ejects but does not lock back. Note how little difference there is between the two settings.

The lock back test is the real way to tell how well an AR is tuned.

Before doing any tuning, make sure your ejector, ejector spring, extractor and extractor spring is in spec. If not, you'll get a false reading

 

[Varminterror]

It does take an H3 buffer to match the weight of a rifle buffer - for those inexplicably motivated to match their Carbine's action masses to that of an M16A2 rifle. H and H2 are too light.

 

[BSA1]

Thanks for all of the replies.

I brought a complete upper from JSE Surplus so I don't know the size of the gas port. There is so much information (and misinformation) about the AR-15 I may be overly concerned about overgassing.

To summarize the advice I am receiving is a) the gun should run fine with a carbine buffer and b) the only real harm to trying a heavier buffer is too my wallet by buying a buffer that will not let the gun run properly with my loads.

This experience will also be useful for me as I am planning on doing my next build from scratch.

 

[Varminterror]

There is so much information (and misinformation) about the AR-15 I may be overly concerned about overgassing.

It's pretty simple - your rifle and brass will tell you if it's over-gassed, just have to know what to look for. Case head swipe and extractor damage are dead give-always it's opening before the pressure spike has subsided. A heavier buffer and an adjustable gas block will eliminate any over gassing issue if you find one. You should be concerned, because it's a problem you should fix IF YOU HAVE IT, but you shouldn't be too concerned, as it's not too difficult to diagnose and not difficult to resolve IF YOU HAVE IT. Most likely, you will have some over-gassing sign, it's painfully common with factory models in the last 10-15yrs.

 

[BSA1]

Roger that Varminterror.

I need to get my outside pre-winter projects done so I can get some quality time on the reloading bench.