Slugging bore in my glock. Issues.

C

Chainsaw.

New member
So I slugged the bore in my glock. High sides are 355, lows are ~347.

I size some bullets to 357, load them, chember them, STUCK. I have to basically motar the slide to get the round out. I can get a sizer to 356 but I highly doubt a thou is gonna be the difference that will make these run.

What the heck am I missing?
 
sounds to me like you are not seating the bullets deep enough. I had a similar problem loading for my 1911 first time I loaded cast... but my slide would not close fully without a push.

try taking one bullet, then progressively set it a hair deeper incrementally, testing it in the barrel. if it is the seating, it should fit after a few adjustments. once you get it where you want it, resize the rest.
 
when you eject an unfired round, are the lands marking the bullet at all?

also, what does the case neck measure on the loaded round?
 
No. No lands. That was the first thing I looked at. With a magnifying glass no less.

I measured the case neck but have since forgot and then I dropped my calipers in the midst of this project
 
that would be my next guess, that the case mouth is too large. maybe a bit more crimp would help. if you are flaring the necks then adjusting the crimp by feel, it may be bringing the flare back down, but not enough.



also, not sure why this didn't jump out at me first, but if this brass has been fired from your Glock or another gun with a partially unsupported chamber, did you run it through a bulge buster? I loaded some brass shot by a Glock for my .40 Walther, and it was bulged so bad it would not chamber. bulge buster fixed it. if that is the problem, it would be visible to the naked eye when you spin the case in your fingers.
 
WHile not a Glock, I size all of my cast for my two Sig,s to .356" and they just eat them up. No issues what so ever. I would give it a try and see. That .001 extra on the bullet, plus any springback will add to the differences of the brass thickness and could be causing your issues.

Don't know that for sure, but it sounds good...;)
 
Nemesis, it is range brass which I full length size. Not having the buldge issue, Ive ran thousands of reloads with jacketed bullets with no issue.

MikeTx, my thought is to size smaller but I wanted to make an informed decision before I throw more money at another bullet sizer.
 
Ok I had my machinist buddy measure some stuff for me when I got to work.

Copper jacket bullets mic to 354. Loaded the neck mics 378.

My cast/sized bullets mic 357 to 357.5. Loaded their neck mics 379.5

My bore slug measures 347 on the small and 355 on the large.

Im guessing the extra 1.5 thousandth on the neck is jamming me up. Thats enough to cause an interferance fit. I guess i get a smaller sizer?
 
That .001 extra on the bullet, plus any springback will add to the differences of the brass thickness and could be causing your issues.
Click to expand...

My thoughts as well. .356 is kind of a lead "standard" for 9mm. Interesting to note that some .380s run into the same problem when suing cast bullets sized at .356 instead of .355.
 
Before changing anything, you should try a "plunk" test. Drop a dummy round into the barrel and see if it fully chambers.

While I don't own a Glock, I do own four 9mm's, and all of them will accept a .357" diameter bullet IF it is properly seated in the case.

Cartridge specs show a case mouth diameter of .380".....so you are within specs. See post #2.
 
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Take a sharpie and color the top 1/4 inch of the brass + the bottom part of the bullet to see where it is jamming. My guess is that seating the bullets deeper will fix it. Especially if there is any of the full bullet diameter above the case mouth. COL from a book doesn't mean much if they don't plunk in your barrel, and you would need a fairly hot load to start with and a lot more than .030 deeper to have pressure issues IMHO.
 
9mm headspaces on the mouth. There is a step in the chamber for the casing mouth to rest on. Beyond the step is the leade, which narrows into the riflings.

When a round is chambered, the bullet resides in the leade. Cast bullets are usually slightly bigger than the groove diameter. But it should be smaller than the leade, or you will have problem chambering. The problem may be insignificant if you have round nose bullet profile. But it may become a real headache if you have semi wadcutter. The sharp shoulder will stop the round from going in cold. I bet you have semi wadcutter.

The solution is to seat the bullet deeper, so that the bullet shoulder comes almost flush with the case mouth. If you concern heightened pressure, you just lighten the charge slightly to compensate. It is probably not needed as cast bullets loads are usually nowhere close to the max.

I had similar problem in some of my pistols, that may have tight leades. That's how I fix it.

-TL
 
Round ball should be much less a problem. Try seating the bullet deeper till the bullet ogive is slightly below the case mouth. If you still have difficulty chambering, the cause is not in the leade, but in the chamber. The bullet plus case wall is too big to go in the tight chamber.

If that's the case, assuming you didn't seat the bullet crooked, and you crimped down the belling at the brass mouth, and you don't want to enlarge the chamber, the solution is to reduce the loaded round's diameter.

A few methods for that. Lee's fcd is one. But it is not my favorite. It is a form of post-sizing that squeezes down the bullet, which negates the point of slight over sized cast bullet. Brass with thinner wall may be the best bet. RP is one the brands that have this "feature".

Hope this helps.

-TL
 
Welp. I think I got it figured out. Got a new set of calipers and a 356 bullet sizer in the mail so I got to puttering. Between sizing the bullets a tad smaller and setting the c.o.a.l back 5 thousandths I got them to run. I can rack the slide clear with no issue. Thanks for you help guys.
 
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