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Posted: 1/22/2011 8:14:24 PM EDT
Having some problems guys seeing if you can help. I've got a dedicated 9mm upper with a tros 5.5 in barell. The breech is so tight that rounds don't want to come out. Just now it ripped the case out but left the bullet in the breech. Below are some pics. Any help would be awesome

This is where hand fed rounds decide they've gone far enough




Link Posted: 1/23/2011 4:38:35 AM EDT
Is this a brand new barrel? Either the chamber isn't really a 9mm chamber, or your ammo is WAY out of spec.
Link Posted: 1/23/2011 6:04:46 AM EDT
Replied to in the duplicate post above in the tacked 9mm FAQ around 5am this morning..

Factory or handloaded ammo sticking ??

Possible need of chamber cleanup ??


I set mine up to look like this with a .745 case not seen with reamer (NOTE –– extractor removed for inspection) ––







Link Posted: 1/23/2011 4:33:40 PM EDT
Originally Posted By aimforthemedic:
The breech is so tight that rounds don't want to come out. Just now it ripped the case out but left the bullet in the breech.

It looks to me like the bearing surface on your bullets are basically jamming into the rifling - either the throat was cut too short (or not cut at all - rough ream and no finish ream possibly), your bullets are loaded way too long, or a combination of the two...

You need to check both your ammo and your chamber. Wouldn't hurt to check your chamber with a GO/NO GO gauge also.

What kind of ammo are you running - heavy 147's or 115/124's? I guess 147's.
Link Posted: 1/23/2011 4:41:22 PM EDT
I checked the tros website they said they make their chambers tighter than standard for more stability...guess it's normal. Only the test fire will tell. I'm running light loads through it right now until my supressor comes through.
Link Posted: 1/23/2011 6:09:16 PM EDT
Originally Posted By aimforthemedic:
I checked the tros website they said they make their chambers tighter than standard for more stability...guess it's normal. Only the test fire will tell. I'm running light loads through it right now until my supressor comes through.


Sounds rather silly to me.. aint never heard of your typical pistol having tight chamber for more stability... unless they ground piss out of reamer for extremely short leade..

Anyway, take your bolt and pop the exctractor out of it,,, drop a sized-empty case in chamber (assuming you handload 9x19), and place bolt back into upper and close it on the case in the chamber,,, take a good clean clear pic like I provided to see what you.

Seems to me somebody else had a problem a yr or so ago with a TROS barrel here.
Link Posted: 1/23/2011 6:13:59 PM EDT
Are those hand loads or factory loads?

If hand loads could be glock brass swelled at the base? need to be run through a full sizing die if thats the case. also if the case came out but left the bullet in the chamber you arent crimping your bullets good enough.
Link Posted: 1/23/2011 6:38:48 PM EDT
I mainly run once fired, factory reloaded rounds from luckygunner.com

I think the round that got pulled apart was just a bad load
Link Posted: 1/23/2011 6:43:07 PM EDT
Also here's the picture

Link Posted: 1/23/2011 6:56:05 PM EDT
[Last Edit: 1/23/2011 7:01:53 PM EDT by SBR7_11]
Originally Posted By aimforthemedic:
Also here's the picture



Oh MY!!!!!

I thought the web of the case looked rather unsupported (you'll ballon you cases at web).... that thing has a rather short chamber...

I cut my barrels and chambers to leave approx 0.130-0.135 case head exposed from barrel face,,,, then with the 0.125 pocket on bolt face, that leave me with a 0.005 to 0.010 air gap from face of bolt to face of chamber... yours is way out of whack !!

Look at my pics closely... you can barely see the air gap from bolt face to barrel end.. That barrel is all WRONG..... Kevin should agree with me there

Dont even waste your loads/brass in that chamber...


Send the barrel back,,, include note with stating the chamber is toooooo short, include your pic, and my pics,, your bolt, and tell them you want your bolt and chamber to match that as seen in my pics.. send them an e-mail with link to this topic for them to see...
Link Posted: 1/24/2011 4:06:58 AM EDT
Let's see a pic of the rounds you are trying to jam into that barrel first.

It is never advisable to do a test fire before all safety checks are done and passed - one of the most important after a function check is a chamber check. If a gun doesn't pass all safety checks, do not pass go, do not live fire it. If you test fire with rounds sticking out of the chamber like yours with the bullet likely jammed into the rifling, you are likely to see some pressure spikes. If you are lucky, you'll just balloon the case where it is unsupported. if you are unlucky, you will have case blowouts which could send shrapnel out the ejection port...
Link Posted: 1/24/2011 4:12:13 AM EDT
[Last Edit: 1/24/2011 4:14:15 AM EDT by CyberIntel]
I have had nothing but good luck with my TROS 10: barel. I would call or email Mark at TROS. Also I didn;t see the answer, are these reloads? I would suggest the Dillon case gauge for checking the ammo.

ETA: OK I see the ammo is from something called "Luckygunner". I'm sure it's fine, but you also might want to try ammo from Winchester or Federal.
Link Posted: 1/24/2011 8:51:39 AM EDT
I'm shooting mil spec M882 ball once fired, factory reloaded. Luckgunner.com is just an ammo retailer not a brand. I'm going to email Tros about it and see what they can do for me.
Link Posted: 1/24/2011 10:05:43 AM EDT
[Last Edit: 1/24/2011 10:05:59 AM EDT by kevins_garage]
Before you contact TROS, it might behoove you to drop a few rounds of some factory loaded ammo (like some WWB or similar) into the chamber to see if it too sticks out in the same manner...

If TROS has their own spec for their chamber reamers and it is tighter than SAAMI spec, it is possible that their barrel could be "in spec" as far as they are concerned, but may not allow all SAAMI spec ammo to feed/function properly...
Link Posted: 1/24/2011 4:39:57 PM EDT
Originally Posted By aimforthemedic:
I'm shooting mil spec M882 ball once fired, factory reloaded. Luckgunner.com is just an ammo retailer not a brand. I'm going to email Tros about it and see what they can do for me.


Did you buy this barrel from them new ?

Any word via E-Mail yet ?
Link Posted: 1/26/2011 6:25:39 PM EDT
Update, new pic of round chambered by rack and release. Previous picture was of hand fed round on bolt. Does it look ok now? There's almost no gap between carrier and receiver

Link Posted: 1/27/2011 7:48:15 AM EDT
Originally Posted By aimforthemedic:
Does it look ok now?

No.
Link Posted: 1/27/2011 2:28:48 PM EDT
[Last Edit: 1/27/2011 2:31:16 PM EDT by SBR7_11]
Originally Posted By kevins_garage:
Originally Posted By aimforthemedic:
Does it look ok now?

No.


I'm with Kevin, the angle and the looks of the gap from bolt face to barrel face look kinda wide yet..

You have a feeler gauge set ?
Measure the gap there,,, anything over 0.010 bother me..




Or a depth micrometer ?
With the depth micrometer, remove barrel, set a case in the chamber, and measure how far the case sticks out beyond barrel face... I'll let you hsve 0.135"..

Link Posted: 1/27/2011 3:27:00 PM EDT
Another vote for "not good at all." The bolt should "kiss" the rear of the chamber, with perhaps a couple sheets of printer paper space between bolt and barrel at most. See SBR7_11's last picture from his 23Jan post. Your picture shows a very much unsupported case web-a real recipe for very unpleasant results when you pull the trigger.
Link Posted: 1/27/2011 3:55:50 PM EDT
Originally Posted By GHPorter:
Your picture shows a very much unsupported case web-a real recipe for very unpleasant results when you pull the trigger.


Something like this but worse ?



Link Posted: 1/28/2011 2:06:45 PM EDT
Originally Posted By GHPorter:
Another vote for "not good at all." The bolt should "kiss" the rear of the chamber, with perhaps a couple sheets of printer paper space between bolt and barrel at most. See SBR7_11's last picture from his 23Jan post. Your picture shows a very much unsupported case web-a real recipe for very unpleasant results when you pull the trigger.

If the chamber is cut to proper SAAMI specs, there should be absolutely no gap at all between the bolt and barrel - the bolt should contact the barrel.
Link Posted: 1/29/2011 6:34:36 AM EDT
Originally Posted By kevins_garage:
Originally Posted By GHPorter:
Another vote for "not good at all." The bolt should "kiss" the rear of the chamber, with perhaps a couple sheets of printer paper space between bolt and barrel at most. See SBR7_11's last picture from his 23Jan post. Your picture shows a very much unsupported case web-a real recipe for very unpleasant results when you pull the trigger.

If the chamber is cut to proper SAAMI specs, there should be absolutely no gap at all between the bolt and barrel - the bolt should contact the barrel.


Agreed. Assuming the basic 20 pound bond paper thickness of 0.0035" to 0.004" thickness, my "at most" winds up to be 0.007" to 0.008". I think less than 0.01" clearance is safe, if not ideal. Any more would certainly be unacceptable. I don't have access to what is considered the standard tolerances for either a 9mm AR barrel or bolt; assuming variations between different makers' tolerances to remain in the "low thousandths" range, stacking of less than 0.008" seems a reasonable expectation.
Link Posted: 1/29/2011 9:32:47 AM EDT
Originally Posted By GHPorter:
Originally Posted By kevins_garage:
Originally Posted By GHPorter:
Another vote for "not good at all." The bolt should "kiss" the rear of the chamber, with perhaps a couple sheets of printer paper space between bolt and barrel at most. See SBR7_11's last picture from his 23Jan post. Your picture shows a very much unsupported case web-a real recipe for very unpleasant results when you pull the trigger.

If the chamber is cut to proper SAAMI specs, there should be absolutely no gap at all between the bolt and barrel - the bolt should contact the barrel.


Agreed. Assuming the basic 20 pound bond paper thickness of 0.0035" to 0.004" thickness, my "at most" winds up to be 0.007" to 0.008". I think less than 0.01" clearance is safe, if not ideal. Any more would certainly be unacceptable. I don't have access to what is considered the standard tolerances for either a 9mm AR barrel or bolt; assuming variations between different makers' tolerances to remain in the "low thousandths" range, stacking of less than 0.008" seems a reasonable expectation.

There are no "clearances" between the bolt and barrel. The contact surfaces of both the bolt and the barrel should be flat and allow full contact. Since the recess in the bolt face serves as a part of the chamber, you will likely have a radius/chamfer around the chamber to aid in feeding and the recess on the bolt can/will have a radius on the edge, but there should be absolutely no gap between the bolt and barrel whether a round is chambered or not... if the bolt stands proud of the barrel, something is wrong...
Link Posted: 1/29/2011 12:43:45 PM EDT
Originally Posted By kevins_garage:
There are no "clearances" between the bolt and barrel. The contact surfaces of both the bolt and the barrel should be flat and allow full contact. Since the recess in the bolt face serves as a part of the chamber, you will likely have a radius/chamfer around the chamber to aid in feeding and the recess on the bolt can/will have a radius on the edge, but there should be absolutely no gap between the bolt and barrel whether a round is chambered or not... if the bolt stands proud of the barrel, something is wrong...
I'm not disagreeing. But I'll bet some makers will weasel around about tolerances in how deep the bolt face is and not do anything about a problem like this.

This is obviously a case of the chamber bored WAY too shallow. From the amount of case shown outside the chamber, it looks a whole lot like the chamber is more bored for a .380 ACP...

Link Posted: 1/29/2011 7:07:10 PM EDT
Originally Posted By GHPorter:
Originally Posted By kevins_garage:
There are no "clearances" between the bolt and barrel. The contact surfaces of both the bolt and the barrel should be flat and allow full contact. Since the recess in the bolt face serves as a part of the chamber, you will likely have a radius/chamfer around the chamber to aid in feeding and the recess on the bolt can/will have a radius on the edge, but there should be absolutely no gap between the bolt and barrel whether a round is chambered or not... if the bolt stands proud of the barrel, something is wrong...
I'm not disagreeing. But I'll bet some makers will weasel around about tolerances in how deep the bolt face is and not do anything about a problem like this.

This is obviously a case of the chamber bored WAY too shallow. From the amount of case shown outside the chamber, it looks a whole lot like the chamber is more bored for a .380 ACP...

I hear ya. I don't know about you or anyone else, but I've never had any problems with first run parts - Colt or RRA 9mm bolts or Colt, RRA, Spikes, or even M1S 9mm barrels. I have mixed and matched different bolts and different barrels and they always pass chamber checks - none have been too tight and none have been too loose. There should be no reason for any parts maker to weasel out on anything if they are making their parts to spec. Sure you can run into tolerance stack issues when you combine parts from multiple different makers, but they shouldn't be any worse than tolerance stack issues among parts all from the same maker - as long as everyone is following the same prints and tolerance limits.

It's hard to tell from the pics whether the chamber is cut to spec and the throat is uncut/unfinished or if the chamber is actually cut too short. This is where a set of GO/NO GO gauges would come in handy to confirm if the chamber is cut to spec or not. Once you know that, you can either look at the throat and/or the ammo if the gun passes GO/NO GO checks or have the chamber re-cut properly if it doesn't pass GO/NO GO checks...
Link Posted: 1/29/2011 7:13:01 PM EDT
I never thought to look up go/no-go gages for 9mmX19 until now.

At Midway, PTG's GO Gage, 9mm Luger, and their NO-GO Gage, 9mm Luger are each $34.99. Not bad prices. Certainly anybody selling barrels they ream the chambers for should have these on hand...
Link Posted: 1/30/2011 6:41:05 AM EDT
Those that don't want to buy them, can make their own if they have the skills and tools to do so...
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