9mm bore diameter on the big size?

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Luke Duke

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I have a question for you guy's? I have recently purchased new a 9mm G.......... :eek: wrong web sight I Get It! But, I trust the opinions here more than any anywhere else. So here we go. This New barrel won't shoot .355 bullets with any acceptable accuracy; 7-10 yards you will hit. But, for a full size gun I was expecting WAY better. Jumped up to .356 coated 147's , way better. Found some bullets I cast in a Lee 124 TL that always cast big at .357 with LinoType. Try them out . Boom, one ragged hole with 15 rounds at 15 yards. After wasting 100nrds of precious primers, that's the diameter it likes? I used this mold for easy .38's.
Now the big question. If this barrel is that over bore would it be safe to use 110gr 38/357 HP's? I don't like carrying a FMJ / HARD Cast for SD , but this gun is 100% unquestionably reliable. And shoots spot on with .357 sized hard cast coated bullets????
 
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When it comes to cast, most 9mm's seem to shoot better with oversized bullets cast on the hard side, or with a gas check. You can use your .357 bullets safely, it is just a question of feeding reliability and bullet seating depth. You might also run into problems with chambering if you have a tight chamber - Sometimes a "fat" bullet, and thick brass may not fully chamber. Most all I have loaded for will handle a .357 bullet fine.

Just start 10% low, and work up. It seems most auto pistols will shoot an undersized jacketed bullet better than a like cast. I would think it's because the harder jacketed bullet holds the rifling better.

Larry
 
I’d be tempted to bend the factory’s ear and see if you can get a new barrel. You might get lucky!
 
I don't own any Glocks but I was under the impression Glock states that the use of lead bullets is a BIG NO- NO! I know there are some after market barrels that are OK to shoot lead out of as they do not use the same type of polygonal rifling.
 
Myself, I'd be extremely careful if You're going to use oversized jacketed bullets in any firearm.

Several years ago I was swaging 2 different sized jacketed bullets for the 44spl/mags. I was making a .429" & a .431" bullet. The larger .431" bullet was for a specific firearm that had oversized cylinder holes. Eventually I sold that firearm and had a couple hundred of the oversized bullets left.

I decided to do a little experiment and loaded up 12 rounds. 6 with the .429" bullet, 6 with the .431" bullet. I used a middle of the road load that I've used in the past (+/- 25,000psi). Put 6 of the .429" bullets in a s&w 629 and shot them off. They performed as expected seeing how I developed that bullet/load combo for that pistol and have shot several hundred of them in that 629.

I put the 6 reloads with the .431" bullet in that 629 and shot them off. Accuracy was a little off but that could of easily been me. The big surprise was when I tried to eject the spent cases. They all were stuck in the cylinder holes. Huge pressure difference!!!!!

Same powder & amount of powder/same cases/same firearm/both reloads shot within minutes of each other/same lead cores and jackets used for all swaged bullets/etc. The only difference was using a jacketed bullet 2/1000th's larger in diameter.
 
My Beretta 92FS wouldn't shoot for beans. Slugged the barrel and as it turned out it slugged at .357. At the time Midway has a sale of Remington .357 125 grain hollow points. So bought a box of 1000. Started low with the powder charge and accuracy improved noticeably. Sadly that bullet later on was discontinued. Now hoarding the few I have. Beretta wasn't much help on the oversized barrel. Frank
 
If the OP's "full size gun"' happens to be a G17 there are quite a few barrels at AIM Surplus that can be had for next to nothing (as in "under a C-note":eek:)...

Their DLC (Diamond Like Coating) G17 barrel is currently under $40! A threaded one for a Gen 5 is $5.00 more!

I have a couple of these AIM Surplus DLC barrels (mine are both ported, BTW) and they shoot just fine: they have conventional rifling too.

Cheers!

P.S. In so far as using jacketed .357" bullets for reloading in his current barrel, safely working up to an acceptable velocity should be easy. If they chamber and fire accurately I would inspect the barrel for any unusual copper buildup, but lacking that what would be the downside?:confused:
 
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I used to have Glocks but contrary to popular wisdom I found mine to not be 100% reliable. Even with factory ammo. So they are gone. While I had them I did get aftermarket barrels for cast bullet shooting.
Glock does not recommend cast in their barrels but I tried it and they shot but I do not recall how well. I do not remember any problems either but has been a while since I had them so I may have forgotten.
I just never got to excited about them.
 
Gen 1-4 Glocks used a polygonal rifling. The bore is actually smaller than barrels with traditional rifling. The Glock barrel supposedly squeezes the bullet into the polygon shape to create a seal and impart spin. The Gen 5's have sort of a hybrid poly/conventional rifling. Glock has always said not to use cast bullets but a lot of people shoot them with no issues. I'm not a Glock guy so I couldn't say why a supposedly smaller bore would favor a bigger bullet but it may have to do with the way lead bullets behave in this system. That or you got a lemon.
 
Took me a while but I found a picture in my files that might shed some light on 38's in a 9mm pistol.
Enjoy.

It may work in some pistols, if over bored.
Be safe.
 
Luke Duke said:
This New barrel won't shoot .355 bullets with any acceptable accuracy; 7-10 yards you will hit. But, for a full size gun I was expecting WAY better. Jumped up to .356 coated 147's , way better. Found some bullets I cast in a Lee 124 TL that always cast big at .357 with LinoType. Try them out . Boom, one ragged hole with 15 rounds at 15 yards.
Click to expand...

I have always thought 9 mm bullets were 0.356. Wouldn't 0.355 be undersized?
 
Marksman barrel

Like I said this gun has been 100% reliable. Its a Gen 5-17 with the Marksman barrel. After shooting lead or coated bullets it cleans up easy, not a trace of leading. Haven't slugged it. Most factory shoots acceptable at 7 yards. I've reloaded a bunch of .355 bullets though, the
best accuracy I've got is with Hornady 147's. With the amount of precious primers I've used up I could have bought a nice after market barrel.
How would you slug this barrel?
 
Nevada Ed said:
Took me a while but I found a picture in my files that might shed some light on 38's in a 9mm pistol.
Enjoy.

It may work in some pistols, if over bored.
Be safe.
Click to expand...

I'm lucky if get that at 15 yards! What gun was these shot in?
 
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When Ed answers you are probably going to be surprised...?

Cheers!

P.S. For $45 you could also be shooting 9mm: how could you lose?
 
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