Warning

 

Close

Confirm Action

Are you sure you wish to do this?

Confirm Cancel
BCM
User Panel

Page AR-15 » AR Pistols
AR Sponsor: bravocompany
Posted: 10/15/2020 3:56:50 PM EDT
I have a ‘problem child’ I’m seeking some input for.  I bought a 7.5” 5.56 upper for a flame-thrower/range toy.  I want to stress that I knew it was going to be a novelty-only pistol going in, so I admittedly bought some low end stuff.  That said, for some dumbass reason I am a glutton for punishment and determined to make this thing run as well as the rest of my AR’s.  I’ve tried the following buffers:  C, H, H1, H2 & H3 (currently in it).  This past weekend with the H3, I still got two stove pipe failures out of 40 rounds and the rifle ejects so forcibly forward that it has been chewing up the rear right side of the quad rail.  Never seen that before on any of my other rifles or AR pistols and cannot seem to stop it from happening.

I’m getting tired of wasting ammo on it and definitely should not have skimped on the cheap upper (Radical Firearms), but the tinkerer in me is nagging me to keep trying to fix something I should maybe just stop shooting...
Link Posted: 10/15/2020 5:10:06 PM EDT
[#1]
Three words for you.

1) Adjustable

2) Gas

3) Block
Link Posted: 10/15/2020 5:12:41 PM EDT
[#2]
I have an 8.5" it runs fine.

I think it was from PSA.

I suspect you have a very large gas hole.
Link Posted: 10/15/2020 5:45:03 PM EDT
[#3]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Three words for you.

1) Adjustable

2) Gas

3) Block
View Quote

fpni
Link Posted: 10/15/2020 6:37:44 PM EDT
[#4]
I anticipated that response, but hate to sink much more money into this thing. Any suggestions for a decent, affordable adjustable gas block?  I’m looking online, but not sure where to start.  Don’t really want to put a Ferrari part in my Poison Pinto...
Link Posted: 10/15/2020 7:27:07 PM EDT
[#5]
I thought some one sold a restricted orfice gas tube.
Link Posted: 10/15/2020 8:04:46 PM EDT
[#6]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
I anticipated that response, but hate to sink much more money into this thing. Any suggestions for a decent, affordable adjustable gas block?  I’m looking online, but not sure where to start.  Don’t really want to put a Ferrari part in my Poison Pinto...
View Quote


@Vehemence

What's the journal diameter? I have an adjustable GB laying around.
Link Posted: 10/15/2020 10:53:26 PM EDT
[#7]
$50-70 for a block is pretty reasonable IMO
Link Posted: 10/15/2020 11:38:40 PM EDT
[#8]
Get a BRT reduced port gas tube it'll help and there like 30 bucks.
Link Posted: 10/16/2020 3:35:52 PM EDT
[#9]
Thanks for the suggestions, folks.  I appreciate your time.
Link Posted: 10/24/2020 2:08:59 PM EDT
[#10]
Have you tried a different BCG?
How does the recoil feel?
Personally I've never had a problem with radical. I've used a couple barrels and a barreled upper but never thier BCG. I'm wondering if it's really over gassed or you've got a weak ejector.
I don't know how the hell it's chewing up your rail. That's crazy! I don't know how that's even possible.
Link Posted: 10/24/2020 3:13:16 PM EDT
[#11]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
I thought some one sold a restricted orfice gas tube.
View Quote


Saw one somehwere online in the past week but I don't recall which vendor.
Link Posted: 10/25/2020 4:58:59 AM EDT
[#12]
Adjustable gas block.
I used this on another pistol and it works well
$19.95. With shipping a little over $28.
You may want to keep the H3 buffer with the AGB from the sounds of it.
BTW, with the right ammo that pistol doesn't have to be a range toy.

Luth Adjustable Gas Block
Link Posted: 10/27/2020 3:01:42 PM EDT
[#13]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Have you tried a different BCG?
How does the recoil feel?
Personally I've never had a problem with radical. I've used a couple barrels and a barreled upper but never thier BCG. I'm wondering if it's really over gassed or you've got a weak ejector.
I don't know how the hell it's chewing up your rail. That's crazy! I don't know how that's even possible.
View Quote



I agree, it is bizarre. It currently (and in the photos below) has a nickel PSA bolt carrier group, but I have tried my BCM BCGs, my RRA BCGs and another “premium” PSA BCG (chuckling to myself after typing that) and have had the same results with all of them.

I guess I will go ahead and get the adjustable gas block, hopefully that will fix it, but again, I’ve never seen anything eject that way. There is a little black touch up paint over some of the marring, but you can still see it in the pics below. Not only has it been chewing up the rail, but also chewing up the forward part of the ejection port. Good times.

Attachment Attached File


Attachment Attached File


Attachment Attached File


ETA:  someone above mentioned it could be a weak extractor, but I have used a BCM extractor spring upgrade kit on all of the BCGs that I use for anything shorter than 14.5”.  They all work great in everything else, I’m pretty sure it’s not the BCG.
Link Posted: 10/28/2020 8:20:26 PM EDT
[#14]
WOW

What does you brass look like?

Bent rims? Big dent mid-case? Case mouth chewed up after chewing up the rail?

Never seen this, exciting!
Link Posted: 10/28/2020 9:55:43 PM EDT
[#15]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
WOW

What does you brass look like?

Bent rims? Big dent mid-case? Case mouth chewed up after chewing up the rail?

Never seen this, exciting!
View Quote


I wish it were exciting, but it’s actually just really irritating (and an expensive waste of ammo). Admittedly, I should’ve inspected the spent brass.  Definitely saw large dents in the middle of the stove piped casings after dislodging them, but did not inspect the rims or mouthes of those that didn’t jam.  (and the non-jammers were obviously the culprits)  Oops...

That said, I was by myself every time at an indoor range that is always littered with tons of spent brass everywhere, like peanut shells on the floor of a Texas steakhouse.  Not to mention the crazy-ass, rail-beating, unpredictable ricochet trajectories of the ejected cases. I have no idea where the hell they ended up.  In retrospect, and thanks to your inquiry, next time I’ll mark the rounds before firing them so I can locate them for inspection.

Thanks for your polite, if unintended nudge.  


Link Posted: 11/1/2020 7:55:47 AM EDT
[#16]
Link Posted: 11/2/2020 12:10:46 AM EDT
[#17]
Had same issue with 7.5 barrel. Round fired then jammed. Got adjustable gas block. Solved problems. No jams, in process of finding right setting for adjustable gas block.
Not an expert, just trying to help.
Link Posted: 11/2/2020 12:23:37 AM EDT
[#18]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
I anticipated that response, but hate to sink much more money into this thing. Any suggestions for a decent, affordable adjustable gas block?  I’m looking online, but not sure where to start.  Don’t really want to put a Ferrari part in my Poison Pinto...
View Quote



Primary Arms...

Good Stuff - Very Affordable - Free Shipping - Super Customer Service if you have any issues.

Adjustable gas block is Definitely what I'd do, and I'd get it from PA.

BIGGER_HAMMER
Link Posted: 11/5/2020 7:26:35 PM EDT
[#19]
Discussion ForumsJump to Quoted PostQuote History
Quoted:



Primary Arms...

Good Stuff - Very Affordable - Free Shipping - Super Customer Service if you have any issues.

Adjustable gas block is Definitely what I'd do, and I'd get it from PA.

BIGGER_HAMMER
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
I anticipated that response, but hate to sink much more money into this thing. Any suggestions for a decent, affordable adjustable gas block?  I’m looking online, but not sure where to start.  Don’t really want to put a Ferrari part in my Poison Pinto...



Primary Arms...

Good Stuff - Very Affordable - Free Shipping - Super Customer Service if you have any issues.

Adjustable gas block is Definitely what I'd do, and I'd get it from PA.

BIGGER_HAMMER


I love Primary Arms - order today and receive it day-after-tomorrow - with free EXPRESS shipping.  I’ve bought so much stuff from them in the past few years, I should be a stockholder. Been to their storefront too - great group of people, but always busy as all get-out.

Is there a particular model/brand that you would recommend?

Thanks.
Link Posted: 11/5/2020 9:13:27 PM EDT
[#20]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


I love Primary Arms - order today and receive it day-after-tomorrow - with free EXPRESS shipping.  I’ve bought so much stuff from them in the past few years, I should be a stockholder. Been to their storefront too - great group of people, but always busy as all get-out.

Is there a particular model/brand that you would recommend?

Thanks.
View Quote



Can't beat $18 bucks!

https://www.primaryarms.com/aero-precision-low-profile-gas-block-no-logo-.750in-phosphate
Link Posted: 11/14/2020 9:31:57 PM EDT
[#21]
Looking at your photo, is the brass deflector (hump behind the ejection port) have a significant amount of brass markings on it?
If so the brass could be hitting the deflector and "bouncing" forward into the rail.
Definitely needs an adjustable gas block (in my opinion) assuming a .750 diameter I like this gas block (when in stock),
very easy to adjust and doesn't carbon up as bad as some others:  https://palmettostatearmory.com/psa-custom-750-diameter-click-adjustable-gas-block-7811021.html
Link Posted: 11/15/2020 11:04:23 AM EDT
[#22]
Ejecting forward that much makes me think your carriers travel distance may be the issue. Is the rear of the ejection port also getting chewed up? The front of the bolt should stop about 1/8'' forward of the rear of the port cut out when fully charged rearward. If the bolt is traveling too far rearward, it can allow the casing to bounce off the rear of the cut out rather than the deflector---- bouncing directly forward. Adding quarters as spacers at the rear of the buffer tube is an easy way to shorten travel distance.
Link Posted: 11/17/2020 5:23:45 PM EDT
[#23]
I had the same exact issue with my son’s 7.5”... the ejection pattern was actually 12:00-12:30 and with slow motion video found that it was so over gassed that the case was ejecting so early and with such force that brass was bouncing off the case deflector and kicking the empty brass forward into the rail and to the 12 o’clock position.  Other times, it was ejecting so quickly that the empty case would be bounced back into the ejection port and jam UNDER the next live round.  

As others have said, an adjustable gas block fixed it perfectly and now 1,000 rounds later has been flawless....
Link Posted: 11/21/2020 5:23:22 PM EDT
[#24]
following for update.  Hope you get it fixed OP.
Link Posted: 11/26/2020 10:59:35 PM EDT
[#25]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Looking at your photo, is the brass deflector (hump behind the ejection port) have a significant amount of brass markings on it?
If so the brass could be hitting the deflector and "bouncing" forward into the rail.
Definitely needs an adjustable gas block (in my opinion) assuming a .750 diameter I like this gas block (when in stock),
very easy to adjust and doesn't carbon up as bad as some others:  https://palmettostatearmory.com/psa-custom-750-diameter-click-adjustable-gas-block-7811021.html
View Quote

I have that gas block on my new 12" Grendel build.  It was super easy to adjust (only have 5 rounds through it so far).

My only concern is that the product listing says not to use it on a pistol length gas system, so probably a no go for OP.
Link Posted: 11/28/2020 2:30:06 AM EDT
[#26]
B.R.O. Adjustable Gas Block

Thanks for all the feedback and advice. This is the one I am going to go with.  I’ll circle back after I receive, install, and test it out.

Attachment Attached File
Page AR-15 » AR Pistols
AR Sponsor: bravocompany
Close Join Our Mail List to Stay Up To Date! Win a FREE Membership!

Sign up for the ARFCOM weekly newsletter and be entered to win a free ARFCOM membership. One new winner* is announced every week!

You will receive an email every Friday morning featuring the latest chatter from the hottest topics, breaking news surrounding legislation, as well as exclusive deals only available to ARFCOM email subscribers.


By signing up you agree to our User Agreement. *Must have a registered ARFCOM account to win.
Top Top