Having an issue with my new BCM upper - help appreciated

[87GN]

@SA80Dan

If not and for know for sure then fair enough, and times and equipment may well have changed since 08 but this quote from the oft-quoted article:

“On my rifle, I use a Sprinco Super Duty M4 buffer spring as well as a DPMS Extra-Heavy Buffer (it is .2oz lighter than an H3 buffer)”

• sounds like what is now known as a “Red” to me. Sprinco’s own wording is that red is best for some carbine length gas guns.

The “white” is brand new, only been around a month or so - I do think its a good thing they released that.

http://www.defensereview.com/the-big-m4-myth-fouling-caused-by-the-direct-impingement-gas-system-makes-the-m4-unreliable/

4. Use a lower receiver with a Sprinco standard Blue spring and an H-3 buffer

[87GN]

@SA80Dan

Actually that I very much do agree with. If everyone started with than baseline…and then did a bit of meddlin’ one piece at a time…then they’d know for sure what did what.

• ETA - but in this particular case as we are talking about trying to make a rifle (that is otherwise already running perfectly with decent ammo) run with shitty weak ammo, I still say go with Car buffer over H

Do you have a BCM 14.5 midlength?

[SA80Dan]

@87GN

Do you have a BCM 14.5 midlength?

I don’t, but I’ve shot a lot of shitty ammo through one 16" carbine, and two 16" middies, and I’ve done a lot of pissing about with springs and buffers etc - not because I was having or are having any problems either, but because I was experimenting with recoil impulse for purpose of faster follow up shots in “hoser” stages at matches while still retaining reliability with crap ammo I generally use for those close in stages.

My point is simply that the issue as described by the OP with weak ammo is a short stroking one. If you want to increase reliability as it pertains to weak ammo, you are better off going light as possible with the buffer in my experience.

As for the Pannone article(s) we are quoting different pieces regarding different rifles. In addition, I don’t believe he uses Wolf ammo.

[mtdawg169]

@greywolf2112

Thanks to everyone for the assistance.

Question - is it possible to open up my T2 tungsten powder buffer and remove the extra weight to make it into a carbine-weight buffer?

Do not do this! By the time you remove enough powder to get the weight down, you will have much less “buffer” inside your buffer and it will not do its job properly. Just get rid of it and get an H buffer from BCM, it will do its job superbly. 87GN has shown that the T2, is not as effective as a comparably weighted GI buffer. We have way too many folks experimenting with springs and buffers before they ever establish a base line for reliability. The 14.5 mids, just like the SR15, don’t require the up-armored springs and super heavy buffers to run well and shoot soft. In fact, they will usually exhibit problems much sooner when folks start screwing around with the buffer & spring weights. Ii can promise you that the guys who designed these systems, put plenty of thought & testing into it so that you wouldn’t have to.

[87GN]

@SA80Dan

I don’t, but I’ve shot a lot of shitty ammo through one 16" carbine, and two 16" middies, and I’ve done a lot of pissing about with springs and buffers etc - not because I was having or are having any problems either, but because I was experimenting with recoil impulse for purpose of faster follow up shots in “hoser” stages at matches.

My point is simply that the issue as described by the OP with weak ammo is a short stroking one. If you want to increase reliability as it pertains to weak ammo, you are better off going light as possible with the buffer in my experience.

As for the Pannone article(s) we are quoting different pieces regarding different rifles. In addition, I don’t believe he uses Wolf ammo.

As I stated before (and I believe rob_s did as well), I have put a lot of weak ammo through a BCM 14.5" midlength using an H buffer.

I quoted the article simply to give a frame of reference for my earlier statement. If it makes any difference, he told me that he didn’t use the red spring.

[greywolf2112]

I have switched out the spring and the buffer to a regular CAR buffer and have a Colt H buffer on its way to me. I will be getting rid of the T2 buffers I have - I think the main reason I liked them was that they were quiet (I hate rattles and wanted to try and go as quiet as possible) but then I realized that it was sort of stupid to be worrying about that. I’m not some ninja bad-azz operator with stealth powers and I’m sure that once the shooting starts I’d rather have something that WORKS than something that doesn’t have a barely audible rattle - LOL.

Thanks to everyone - I’ve learned my lesson and will from this point on go with the “known” first and if it works I’ll leave it alone - this gear-whoring disease is endemic, isn’t it?

[mtdawg169]

You don’t have to get rid of the T2 if you have another rifle suited to them. Some here hate them, I find myself to be indifferent after trying one out in a standard middie. They will do their job just fine when used with the right setup. I just wouldn’t go pouring out powder to make it into something that it isn’t. I also wouldn’t go out of my way to buy one if I had to choose between it and a GI buffer for a build, I would go GI everytime. OTOH, if I had one on hand and a rifle that functioned reliably with it, I’d use it and save the $$. Its just too heavy for the 14.5 mid and action spring combo you were trying to use.

[SA80Dan]

Greywolf - good call on getting both the H buffer, Car buffer and springs to try…ultimately, despite what any of us here say, that’s the way to go; try and test it all for yourself. We’ve kinda given you steers with what really amounts to a very slight difference of opinion, but one or the other combinations should work for your individual rifle and ammo.

One last thing I will say though is if you are using the earlier Wolf black box or the Tulammo/Herters (all the same stuff), if, nomatter what you do, you do still get the occasional short stroke, I wouldn’t be concerned. I have found as have others that stuff is the worst of the worst as far as being weak and inconsistent goes. Out of my three rifles, the only one that will always cycle it no matter what is my very overgassed M&P15 (which feels decidedly harsh when using full power 5.56). I have found when shooting some lots of that stuff, you can really feel the weaker individual rounds through the rifle. If you stick to the newer Wolf WPA (or the Wolf Mil classic), or the Bears, it is much more consistent and you’ll likely never have a problem other than a very occasional dud primer.

Some more info here:

http://vuurwapenblog.com/2010/12/11/tulammo-223-dont-bother/

[C4IGrant]

@greywolf2112

Brand new BMC mid-length upper, 14.5", with Battlecomp 1.5 brake.

Lower has a CS blue-end spring and Spikes T2 tungsten buffer weight.

Started off shooting Wolf 62 grn poly ammo - everything worked great. Switched over to Federal American Eagle 55 grain and everything worked great. Went back to Wolf and suddenly it wouldn’t strip off the next round out of the mag. Fired fine, ejected fine, but 50% of the time would not strip the next round off the mag. On the last round it wouldn’t push the bolt back far enough to lock the bolt open on the empty mag. But when I went back to the Federal ammo everything worked just right.

Am I correct in assuming that perhaps the Wolf ammo is not as powerful as the Federal and is therefore not giving the bolt enough “oomph” to push it back far enough over the rear of the next round in the magazine to allow for chambering?

Could it be the muzzle brake causing this?

Would I be advised to perhaps try a lighter, shorter buffer spring, or a carbine weight buffer instead of the T2 buffer?

Typically speaking, a middy (especially a 14.5" middy) does not have the force that a 16" carbine or 16" middy would have. Couple that with one of the weakest loads, an H buffer and a spring that does NOT weaken like cheap SS springs does and you have a recipe for short stroking.

If you want to shoot cheap (crappy) ammo in your gun, then you will need to either change out to a spring to one that only has about 10% of its life left (AKA USGI SS buffer spring) or switch to a car buffer.

CS buffer springs are NOT extra power springs (generally speaking). They are just made to last MUCH longer than a SS spring. Your AR requires PM’s in order to run well. This means changing out your buffer spring, extractor spring and extractor insert every 3k-5K. Now I don’t know about you, but I am WAY to busy to remember to do this. So I personally run Tactical SpringCo’s blue CS buffer spring. This way I don’t have to change it out for over 100,000 rounds (or more). So CS springs ARE a good idea AS LONG as you understand to use them and a buffer in a correct manner.

When building a rifle, it is important to understand how much gas your gun actually has, realize if your ammo is under pressured or not and then tune the spring and buffer weight system accordingly.

Here are some general rules:

Mil-Spec Carbines (Colt, DD, BCM, LMT, Etc):

H buffer and CS Buffer Spring
H buffer and SS Buffer Spring
H2 buffer and SS buffer Spring

Non Mil-Spec Carbine (RRA, BM, DPMS, Oly, Etc):

H2 buffer and CS buffer Spring
H2 buffer and SS buffer Spring
H3 buffer and SS buffer Spring

16" Middy AR’s:

Car buffer and a CS buffer spring
H buffer and CS buffer spring (Depends on who made the gun and GP size)
H buffer and SS buffer spring

14.5" Middy AR’s:

Car buffer and SS Spring
H buffer and SS Spring
Car buffer and CS Spring

C4

[C4IGrant]

@Boss_Hogg

I’ve used the Sprinco blue spring in a number of midlengths with zero issues. I’ve even used their rifle spring and 6oz buffer in a Vltor A5 extension w/ a DD 14.5" mid.
When Mike Pannone did his “why doesn’t my AR jam” test that the DI-minati always refer to, he used a Sprinco spring. They’re not aftermarket garbage.

Right. Mr. Pannone has forgotten more about how to make an AR run reliably than most ANYONE (including me) will ever know.

He has and is working with SpringCo to do a chart with gas port size/barrel length and matching CS Buffer Springs.

C4

[SA80Dan]

@C4IGrant

Here are some general rules:

Mil-Spec Carbines (Colt, DD, BCM, LMT, Etc):

H buffer and CS Buffer Spring
H buffer and SS Buffer Spring
H2 buffer and SS buffer Spring

Non Mil-Spec Carbine (RRA, BM, DPMS, Oly, Etc):

H2 buffer and CS buffer Spring
H2 buffer and SS buffer Spring
H3 buffer and SS buffer Spring

16" Middy AR’s:

Car buffer and a CS buffer spring
H buffer and CS buffer spring (Depends on who made the gun and GP size)
H buffer and SS buffer spring

14.5" Middy AR’s:

Car buffer and SS Spring
H buffer and SS Spring
Car buffer and CS Spring

C4

Well shoot, Grant - you just summed up the entire thread in one nice concise post - good stuff! :big_boss:

[C4IGrant]

@SA80Dan

Well shoot, Grant - you just summed up the entire thread in one nice concise post - good stuff! :big_boss:

Thanks. I didn’t read anything other than the OP’s post when I did my post.

C4

[Ironbutt]

Timely thread!

Several times this week I’ve come very close to hitting the “Add to Cart” button for a BCM 14.5 mid length upper. So far I’ve shown monumental restraint, but I’m weakening.

I was going to use a H buffer, but was wondering about the spring. I have a M&P 15 now & I think it would benefit from the H buffer too.

[C4IGrant]

@Ironbutt

Timely thread!

Several times this week I’ve come very close to hitting the “Add to Cart” button for a BCM 14.5 mid length upper. So far I’ve shown monumental restraint, but I’m weakening.

I was going to use a H buffer, but was wondering about the spring. I have a M&P 15 now & I think it would benefit from the H buffer too.

Your M&P is over gassed. So I would run an H2 and CS (blue) Spring.

C4

[Ironbutt]

@C4IGrant

Your M&P is over gassed. So I would run an H2 and CS (blue) Spring.

C4

Thanks!

[SA80Dan]

@C4IGrant

Your M&P is over gassed. So I would run an H2 and CS (blue) Spring.

C4

FWIW, I run a H2 and a Sprinco Red in my M&P15…and as stated, that rifle will even run the worst of the worst near squib rounds of Tulaammo without issue…if they would fit, I reckon I could probably use a car suspension spring and a housebrick for a buffer and it would still cycle. My M&P is my highest round count AR at over 16,000 or so and it has been in that configuration a long time.

[C4IGrant]

@SA80Dan

FWIW, I run a H2 and a Sprinco Red in my M&P15…and as stated, that rifle will even run the worst of the worst near squib rounds of Tulaammo without issue…if they would fit, I reckon I could probably use a car suspension spring and a housebrick for a buffer and it would still cycle. My M&P is my highest round count AR at over 16,000 or so and it has been in that configuration a long time.

This setup “running” doesn’t suprise me.

People often do not understand how much gas a non mil-spec 16" M4 AR has and how to tame it.

You do.

C4

[TomD]

Interesting thread! Is there any way to determine gas port size other than removing the FSB?

[nickdrak]

FWIW, I run an LMT “H” buffer and a SprinCo “Blue” buffer spring in my BCM 14.5" Middy. To be fair, I run the FailZero M4 upper receiver & FailZero F/A BCG in-conjunction with the stripped BCM 14.5" Middy barrel. I never run Wolf. For training I run a mix of Fed or Win XM193 or PMC Bronze. So far 1500rds without any malfunctions.

Duty ammo is Speer 64gr GDSP.

[C4IGrant]

@TomD

Interesting thread! Is there any way to determine gas port size other than removing the FSB?

Yes and no. If it is a certain brand we can almost gurantee it is over gassed.

C4