needa little advice

ADIDAS69 · December 4, 2019, 02:01 PM

having trouble getting a new 10mm build to feed live cartridges. Feeds snap caps just fine. using sellierr and bellot in genuine Glock magazines. The bolt strips the round but the round doesn't orient straight. seems to be getting hung up in the chamber though I cannot see any obvious obstruction. I've polished all the contact surfaces excluding the chamber. The bullet and about 10% of the casing make it into the chamber then it fails to slip onto the bolt face. I'd upload pictures but for some reason a "security tag" is missing from the files and the site won't let me upload them.

**Unclenick** · December 4, 2019, 04:33 PM

Sounds like the mag feed lips aren't letting go of it early enough. Is it FMJ or one of their hollow point bullet designs?

Nathan · December 4, 2019, 06:49 PM

You have to determine what is stopping it.

If I read you right, the bullet is going up the feed ramp.....it almost sounds like the issue is happening at the rear of the case. After the bullet starts up the feed ramp, the mag should release the case head. The release should be able to power its way under the extractor. Sometimes magazines hold on too long(out of spec) or the extractor is too tight.

I’m not sure what 10mm build means. Are you building an 80% Glock type frame and attaching to a Glock type slide?

Onward Allusion · December 5, 2019, 12:03 AM

Assuming that it's a 80% build-out, is everything aligned and squared?

**JohnKSa** · December 5, 2019, 12:25 AM

Is the extractor preventing the case head from sliding up the boltface?

dyl · December 5, 2019, 12:57 AM

Is this an:

AR pistol caliber carbine with a real "bolt"?

Polymer 80% pistol? - in which case we're referring to the breech face of the slide as being the bolt?

If this is a pistol, is there a chance that you've used a wrong upper parts kit and installed an extractor for a smaller caliber? - or perhaps an aftermarket extractor that's not to spec? It could also be the milling of the slide affecting how the extractor sits in the slide and what angle it presents itself. I once had a Spinta Precision slide that wasn't milled out completely near the breech face so I filed the corner of the barrel down to fit.

You could try a new factory extractor if that's the problem.

It might be helpful to know which parts are Glock factory parts, and which are aftermarket. Upper parts kit, barrel, slide, frame....

**44 AMP** · December 5, 2019, 03:34 AM

TO begin with, verify that the snap caps that feed are dimensionally the same as the ammo (which doesn't).

Snap caps are close to live ammo size but not guaranteed to be the same exact size, as they are snap caps, and not dummy rounds.

Also consider this, the WEIGHT of a snap cap is not the same as a live round.

I ran across a 1911 that would feed snap caps, hollow points and ball ammo. It would eject fired cases, snap caps and loaded hollow points but would NOT eject loaded ball ammo. Hollow points ejected ok because they were shorter than loaded ball ammo. I found it interesting that snap caps, the same size as ball ammo would eject just fine, but ACTUAL ball ammo would not eject and would jam in the gun requiring about 3 hands and a screwdriver to clear the round as the slide could not be locked back or barely moved at all once jammed.

It was the weight of the loaded round that when ejection was attempted, gave it a very slightly different angle of travel than the snap cap, and that angle was enough different that the round did not clear the slide and jammed the gun,

Turned out the gun had the wrong ejector installed. Not your issue but I mention it to make the point that sometimes snap caps will show proper function when live ammo won't.

**4V50 Gary** · December 5, 2019, 12:22 PM

Are you racking or are you easing the slide forward?

Dfariswheel · December 5, 2019, 09:16 PM

As above, snap caps are just that...snap caps. They're useless for trouble shooting.
For purposes of trouble shooting problems you need Action Proving Dummies.

These are the exact size, weight, and even balance of live ammo.

Buy these from Brownell's.

https://www.brownells.com/gunsmith-t...prod40860.aspx

ADIDAS69 · December 13, 2019, 03:36 AM

Follow up, after fiddling with with it a bit more gave the top of the upper receiver a proper thump. The bolt closed. After this i sanded the cartridge pushing bit at the 6 o’clock position on the bolt face. Took off about half a millimeter, then polished to a mirror shine. I also put two 0.0010 shims between the upper and the barrel. Thing runs like a champ now.

T. O'Heir · December 14, 2019, 02:07 PM

"...round doesn't orient straight..." That sounds like the back of the chamber might need chamfering. You extend the feed ramp about half way up the sides of the chamber with a fine file. Happened a lot with .45's trying to feed SWC's before they got popular. Most pistols come that way now. A new 10mm barrel may not have it already though.
Have a look at the extractor too. It clean and moving freely?
And look at the mag lips. If the mag is brand new, the lips may have gotten squeezed in a tick. Fixed with needle nosed pliers. A slight tweak to open the lips a wee bit is all you need do.

December 4, 2019, 02:01 PM	#1
ADIDAS69 Senior Member Join Date: October 17, 2009 Location: Seattle Posts: 381	needa little advice having trouble getting a new 10mm build to feed live cartridges. Feeds snap caps just fine. using sellierr and bellot in genuine Glock magazines. The bolt strips the round but the round doesn't orient straight. seems to be getting hung up in the chamber though I cannot see any obvious obstruction. I've polished all the contact surfaces excluding the chamber. The bullet and about 10% of the casing make it into the chamber then it fails to slip onto the bolt face. I'd upload pictures but for some reason a "security tag" is missing from the files and the site won't let me upload them. __________________ "...I would walk with my people if I could find them..."

December 4, 2019, 04:33 PM	#2
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,061	Sounds like the mag feed lips aren't letting go of it early enough. Is it FMJ or one of their hollow point bullet designs? __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

December 5, 2019, 12:03 AM	#4
Onward Allusion Senior Member Join Date: November 17, 2009 Location: Back in a Non-Free State Posts: 3,133	Assuming that it's a 80% build-out, is everything aligned and squared? __________________ Simple as ABC . . . Always Be Carrying

December 5, 2019, 12:25 AM	#5
JohnKSa Staff Join Date: February 12, 2001 Location: DFW Area Posts: 24,973	Is the extractor preventing the case head from sliding up the boltface? __________________ Do you know about the TEXAS State Rifle Association?

December 5, 2019, 03:34 AM	#7
44 AMP Staff Join Date: March 11, 2006 Location: Upper US Posts: 28,819	TO begin with, verify that the snap caps that feed are dimensionally the same as the ammo (which doesn't). Snap caps are close to live ammo size but not guaranteed to be the same exact size, as they are snap caps, and not dummy rounds. Also consider this, the WEIGHT of a snap cap is not the same as a live round. I ran across a 1911 that would feed snap caps, hollow points and ball ammo. It would eject fired cases, snap caps and loaded hollow points but would NOT eject loaded ball ammo. Hollow points ejected ok because they were shorter than loaded ball ammo. I found it interesting that snap caps, the same size as ball ammo would eject just fine, but ACTUAL ball ammo would not eject and would jam in the gun requiring about 3 hands and a screwdriver to clear the round as the slide could not be locked back or barely moved at all once jammed. It was the weight of the loaded round that when ejection was attempted, gave it a very slightly different angle of travel than the snap cap, and that angle was enough different that the round did not clear the slide and jammed the gun, Turned out the gun had the wrong ejector installed. Not your issue but I mention it to make the point that sometimes snap caps will show proper function when live ammo won't. __________________ All else being equal (and it almost never is) bigger bullets tend to work better.

December 4, 2019, 06:49 PM	#3
Nathan Senior Member Join Date: July 1, 2001 Posts: 6,327	You have to determine what is stopping it. If I read you right, the bullet is going up the feed ramp.....it almost sounds like the issue is happening at the rear of the case. After the bullet starts up the feed ramp, the mag should release the case head. The release should be able to power its way under the extractor. Sometimes magazines hold on too long(out of spec) or the extractor is too tight. I’m not sure what 10mm build means. Are you building an 80% Glock type frame and attaching to a Glock type slide?

December 5, 2019, 12:57 AM	#6
dyl Senior Member Join Date: October 31, 2009 Location: Ohio Posts: 1,310	Is this an: AR pistol caliber carbine with a real "bolt"? Polymer 80% pistol? - in which case we're referring to the breech face of the slide as being the bolt? If this is a pistol, is there a chance that you've used a wrong upper parts kit and installed an extractor for a smaller caliber? - or perhaps an aftermarket extractor that's not to spec? It could also be the milling of the slide affecting how the extractor sits in the slide and what angle it presents itself. I once had a Spinta Precision slide that wasn't milled out completely near the breech face so I filed the corner of the barrel down to fit. You could try a new factory extractor if that's the problem. It might be helpful to know which parts are Glock factory parts, and which are aftermarket. Upper parts kit, barrel, slide, frame....

December 5, 2019, 12:22 PM	#8
4V50 Gary Staff Join Date: November 2, 1998 Location: Colorado Posts: 21,832	Are you racking or are you easing the slide forward? __________________ Vigilantibus et non dormientibus jura subveniunt. *Molon Labe!*

December 5, 2019, 09:16 PM	#9
Dfariswheel Senior Member Join Date: May 4, 2001 Posts: 7,478	As above, snap caps are just that...snap caps. They're useless for trouble shooting. For purposes of trouble shooting problems you need Action Proving Dummies. These are the exact size, weight, and even balance of live ammo. Buy these from Brownell's. https://www.brownells.com/gunsmith-t...prod40860.aspx

December 13, 2019, 03:36 AM	#10
ADIDAS69 Senior Member Join Date: October 17, 2009 Location: Seattle Posts: 381	Follow up, after fiddling with with it a bit more gave the top of the upper receiver a proper thump. The bolt closed. After this i sanded the cartridge pushing bit at the 6 o’clock position on the bolt face. Took off about half a millimeter, then polished to a mirror shine. I also put two 0.0010 shims between the upper and the barrel. Thing runs like a champ now. __________________ "...I would walk with my people if I could find them..."

December 14, 2019, 02:07 PM	#11
T. O'Heir Senior Member Join Date: February 13, 2002 Location: Canada Posts: 12,453	"...round doesn't orient straight..." That sounds like the back of the chamber might need chamfering. You extend the feed ramp about half way up the sides of the chamber with a fine file. Happened a lot with .45's trying to feed SWC's before they got popular. Most pistols come that way now. A new 10mm barrel may not have it already though. Have a look at the extractor too. It clean and moving freely? And look at the mag lips. If the mag is brand new, the lips may have gotten squeezed in a tick. Fixed with needle nosed pliers. A slight tweak to open the lips a wee bit is all you need do. __________________ Spelling and grammar count!