9mm Freebore Hand Reamer

[Sniffer]

Howdy, I have an issue with some / most of my 9mm barrels.

I have one gun which I purchased new and have run forever (gun has been a workhorse - probably have 50K at least on it), gun was reworked by someone to make it more race ready when I first got it (changed a bunch of springs / grips for sure) but I suspect they throated the barrel a little too.

Reason I say this is because it was never picky about ammo COAL. My 9mm loads were at 1.10" ish for a long time (which is definitely on the longer side) and it has never had a single issue. Gun is CZ and barrel is standard as came in the gun.

I also have a second gun (same model) and some other barrels (2 CZ Custom barrels) and they are crazy fussy about COAL. Trying to run anything beyond 1.085" is asking for trouble and I have had that gun jam up (ie slide wont go fully forward into battery as the round is already jammed in the rifling). This has happened with both the standard barrel and CZ Customs.

Obviously the easy answer is to stay at 1.085" for length but it seems that even a little variation (progressive press with some flex on the shell plate etc as well and I strongly suspect 9mm bulk bullets are far from 100% uniform in profile - ie variation in bullet ogive) will cause issues so I would like a solution where this is eliminated like my other longstanding barrel.

Is there a tool to hand ream the throat? I mean it will be very minimal. I imagine a reamer that indexes on the end of the 9mm barrel case shoulder (ie it would only remove material until it hits this point and maxs out) and take off a fraction of the initial rifling to add a thou or two of freeborn and make the gun a little less picky on length.

Or am I dreaming?

 

[KotKotofeich]

If I understood correctly you believe your guns are jamming on the projectile. You are sure it's not the brass, i.e. plunk test is good...

So you need a throater reamer. They aren't cheap, maybe there's someone who already has one, I don't, only a chambering one

 

[Sniffer]

If I understood correctly you believe your guns are jamming on the projectile. You are sure it's not the brass, i.e. plunk test is good...

So you need a throater reamer. They aren't cheap, maybe there's someone who already has one, I don't, only a chambering one

Deffo not brass. Brass has been roll sized and then sized with die. Ammo is checked with chamber checker (ie plunk test).

To prove that point the same ammo runs fine in one gun / barrel and jams up like crazy in the other.

So a throater reamer..... (goes off to look that up) - thank you.

 

[I Dont Care About You]

I have an issue with some / most of my 9mm barrels.

If you have an issue with your reloads in multiple barrels, then the issue is your reloads, not the barrels.

Seating depth can easily be altered. You can't unthroat a barrel, once you discover you fukced it up. A neophyte, who doesn't even know what a throwing reamer is, should not be running such a tool into a barrel. The potential for you to fukcitup is VERY high.

What's the problem with seating bullets shorter?

 

[Lodi]

Ammo is checked with chamber checker (ie plunk test).

To prove that point the same ammo runs fine in one gun / barrel and jams up like crazy in the other.

Check the ammo in the actual chamber you are having issues with, not a separate gauge.

A too short throat would be way down the list of suspects for me.
~ Check the barrel for a buildup of crud in the area the bullet resides, carbon and lead are common. Hot loads might be causing a buildup before bullet transitions to rotation.
~ Too strong or weak recoil springs might be a factor.
~ A damaged extractor or too strong a spring might be hampering the case from moving up the breech face.
~ A too long cartridge or incompatible bullet profile might give a momentary 3-point jam, just long enough to defeat the recoil springs oomph.

 

[Sniffer]

If you have an issue with your reloads in multiple barrels, then the issue is your reloads, not the barrels.

Seating depth can easily be altered. You can't unthroat a barrel, once you discover you fukced it up. A neophyte, who doesn't even know what a throwing reamer is, should not be running such a tool into a barrel. The potential for you to fukcitup is VERY high.

What's the problem with seating bullets shorter?

That logic doesn't make sense.

One barrel has never had an issue of any kind despite thousands of rounds of reloads (mostly on the long side) being fired. Two other barrels have given lots of trouble when trying to use the same ammo (or even shorter ammo). As mentioned the ammo is the constant so the barrels have to be the difference.

Forgetting about reloads I have tried some factory ammo and had the same phenomenon. Shoots fine in one barrel and issues in the other.

Pretty sure no one is born knowing what a throating reamer is, everyone will have a first time somewhere along the way.

 

[Sniffer]

Check the ammo in the actual chamber you are having issues with, not a separate gauge.

A too short throat would be way down the list of suspects for me.
~ Check the barrel for a buildup of crud in the area the bullet resides, carbon and lead are common. Hot loads might be causing a buildup before bullet transitions to rotation.
~ Too strong or weak recoil springs might be a factor.
~ A damaged extractor or too strong a spring might be hampering the case from moving up the breech face.
~ A too long cartridge or incompatible bullet profile might give a momentary 3-point jam, just long enough to defeat the recoil springs oomph.

All good things to check but these guns are babied. Cleaned and lubed after every range session. Both guns are setup with the same springs.

The older gun should be more tired but it is the one thats running best (zero issues). All use the same ammo.

When this happens the bullet is deffo stuck in the rifling as it is very hard to extract (generally means using a brass squib rod to tap the bullet back out). I have tried to rack the slide but it is stuck good.

 

[Lodi]

Pour a chamber cast of the good barrel and the bad barrel, compare the two.

 

[Sniffer]

Pour a chamber cast of the good barrel and the bad barrel, compare the two.

Makes sense.

Guessing wax is best for this?

 

[Wally]

Howdy, I have an issue with some / most of my 9mm barrels.

I have one gun which I purchased new and have run forever (gun has been a workhorse - probably have 50K at least on it), gun was reworked by someone to make it more race ready when I first got it (changed a bunch of springs / grips for sure) but I suspect they throated the barrel a little too.

Reason I say this is because it was never picky about ammo COAL. My 9mm loads were at 1.10" ish for a long time (which is definitely on the longer side) and it has never had a single issue. Gun is CZ and barrel is standard as came in the gun.

I also have a second gun (same model) and some other barrels (2 CZ Custom barrels) and they are crazy fussy about COAL. Trying to run anything beyond 1.850" is asking for trouble and I have had that gun jam up (ie slide wont go fully forward into battery as the round is already jammed in the rifling). This has happened with both the standard barrel and CZ Customs.

Obviously the easy answer is to stay at 1.850" for length but it seems that even a little variation (progressive press with some flex on the shell plate etc as well and I strongly suspect 9mm bulk bullets are far from 100% uniform in profile - ie variation in bullet ogive) will cause issues so I would like a solution where this is eliminated like my other longstanding barrel.

Is there a tool to hand ream the throat? I mean it will be very minimal. I imagine a reamer that indexes on the end of the 9mm barrel case shoulder (ie it would only remove material until it hits this point and maxs out) and take off a fraction of the initial rifling to add a thou or two of freeborn and make the gun a little less picky on length.

Or am I dreaming?

You mean 1.085"? 1.850" is a long way from 1.10"

 

[Sniffer]

You mean 1.085"? 1.850" is a long way from 1.10"

Yes, my apologies. I meant 1.085"

 

[Lodi]

Makes sense.

Guessing wax is best for this?

The professional stuff is Cerrosafe, expensive if you don't pour many. In your case I would use sulfur, available at a garden center.

 

[old303]

I've run into a similar issue, but Glock Bulge in occasional pieces of range-floor brass and not having a roll sizer were apparently the issue.

 

[Sniffer]

I've run into a similar issue, but Glock Bulge in occasional pieces of range-floor brass and not having a roll sizer were apparently the issue.

My brass gets roll sized for that exact reason.

Some Glock bulges can be pretty extreme. I found a piece of brass at the range one that must have been close to being a mini pipe bomb. I think I still have it (will dig it out and post a picture).

 

[I Dont Care About You]

Pretty sure no one is born knowing what a throating reamer is, everyone will have a first time somewhere along the way.

Without training and experience you will fukc it up and it is impossible to unfukcitup. But hey, its your barrel and you've been warned.

 

[KotKotofeich]

I agree with what others have said - test the brass in the actual chamber not a gauge.

Cartridges that got stuck - you think it was in the rifling. Do you see the rifling marks on the projectile to support that?

There's a chance the entire chamber is undersized - within spec but room to make bigger while in spec? Then you might be able to just touch it with a chamber reamer...

 

[Sniffer]

Without training and experience you will fukc it up and it is impossible to unfukcitup. But hey, its your barrel and you've been warned.

This is true.

 

[Sniffer]

I agree with what others have said - test the brass in the actual chamber not a gauge.

Cartridges that got stuck - you think it was in the rifling. Do you see the rifling marks on the projectile to support that?

There's a chance the entire chamber is undersized - within spec but room to make bigger while in spec? Then you might be able to just touch it with a chamber reamer...

Yes, there were marks. But I will check it anyways (cant hurt). Will test to see what max length is but I suspect that exercise is somewhat futile as the projectiles are not uniform enough on the ogive (bulk 9mm)

My buddy has the same model of gun and the exact same issue. I always wondered why he was so anal about ammo length (measured every round for competition and it was more than 1.085" it wasn't match ammo) as my gun wasn't fussy at all. Now I understand with my other barrels.

 

[tiriaq]

Brownells lists a Clymer 9mm throating reamer @US$75.
Good cutting fluid, and a gentle touch and the job would be done. Or find a 'smith who has the reamer and can do the job.
This is assuming that throat dimensions are the issue.

 

[sean69]

Hi,
- you are using your ammunition as a measurement tool but built in variances (bullet ogive, OAL/COAL, bulk bullet weigh tolerances etc) make this a very poor way to measure anything. (is crimp a factor? Do you crimp 9mm? I don't know myself)
- Your control (the gun that cycles properly) has had unknown work performed to "improve" it and is possibly worn (50k rounds), making it a poor control subject.

The control functions as expected, the 3 test subjects do not. I would suspect the control is out of tolerance.
You are only talking about removing +0.001 to +0.002 from the rifling from the 3 failing candidates.

If it were me I would actually measure all 4 chambers and find out what was done to the control before going the the expense of trying to ream out 0.002 from your candidates.

Basically your assumption is based on flawed testing/measurement . Once you know what the actual difference is, the solution should reveal itself. (I myself don't see the issue with seating bullets a little shorter)