Corbon is Tight in a 32acp

[christcorp]

I picked up an FEG AP-MBP 7.65 32ACP (Walther PPK Clone). I bought a box of Corbon for PD. After loading a magazine with 7 rounds, I put the safety on and chambered 1 round. I noticed that it seemed like it took a bit more effort to chamber. I tried to MANUALLY eject the round and chamber the next round, and found that I couldn't get the slide to move. The round was too tight in the barrel. It too 2 hand and a lot of strength to extract and eject the round.

So, I dismantled the gun so I had just the frame and barrel totally exposed. If I put in a Blazer or winchester round (That's all else I had); the round seated pretty much all the way down. Even if I pushed the round all the way in with my finger, it only took a finger nail to pull the round out. However, if I put in a Corbon, it seemed to not go in all the way. It was smooth except for that last millimeter or such. If I manually pushed the round in the rest of the way, it would take a small screwdriver on the rim with a lot of effort to extract the round. I tried this with almost the entire box with the same results. Seems like the last millimeter or such of the rounds are a little bit wider and too snug.

Has anyone had any problems with certain brands of ammo not quite fitting correctly? I would have thought Corbon would have been a bit higher on the quality. I have another Walther PPK 32 acp, but my daughter is currently borrowing it. So I don't have another gun to try the ammo in. Any ideas? mike....

 

[LightningMan]

It might be the ammo, but it could be the chamber is tight because the cutting tool went dull and it didn't get noticed. I'm sure they have some sort of tolorence gages (go/no-go plug gages) to check, and this one may have barely passed. If you take the acceptable diamention's of a .32 chamber, there may be a tolorance of +/- .005 and the ammunition has its min/max diamentions as well. I'm assuming the chamber is on the low side and the ammo is on the high side of those measurments. You will need a chamber gage to check to see if there is a problem with it, as another problem could be, that there is some tapper in the chamber (chamber hole gets smaller the closer it gets to the rifling) that should not be there. LM

 

[christcorp]

Thanks for the response. After closer inspection; I got a friend of mine who does a lot of reloading to look at it. He believes that the problem is in the taper crimp of the ammo. As I said, with the gun dismantled, I can drop a blazer or winchester in the barrel and it drops right in. Turn it upside down and the rounds drops out. Put in the Corbon and it goes ALMOST all the way in. If you assist it the rest of the way in, it takes a small screwdriver to extract it out of the chamber.

Specs or not, I have always found some guns that just didn't like certain ammo. (Except my SigSauer P220 which would shoot anything you can find). But it's possible that this gun just doesn't like Corbon. So, I'll go back to the dealer today. I spoke with Corbon, they want me to try a round or two out of another box, and to see if they are the same lot number. If it's still snug and it's the same lot number, let the dealer know to send it back for replacement. If it's still snug and a different lot number, then maybe my gun just doesn't like Corbon. (My words). If that's the case, I'll just swap it for something else. Thanks again,,,, Mike.....

 

[Badger Arms]

Your problem is probably not the chamber, but the throat. The bullet cannot go fully into the throat. It has a different profile than the full-metal jacket Blaser ammo. Your gun was not designed to fire hollow-points. As you've found out, that is why you must test each type of ammo before using it for anything serious.

On a positive note, I will take that pesky worthless ammo off your hands. Just send it to my house and I'll reimburse you for half your shipping. After all, lead disposal fees are pretty steep!

 

[christcorp]

LOL!!! Considering that the dealer in town will simply swap it out for a box of something else, i think I'll go that route. But I DO APPRECIATE you helping me take it off my hands.

Honestly; not sure if the bullet diameter is a little bigger or if it's the crimp. In theory; if it's the bullet, then extraction wouldn't be a problem, because the bullet won't be there and the case would be coming back. No problem. The problem I have, is chambering a round that I CAN'T manually extract if I wanted to.

There are some really go reviews of people using Fiocchi HP in these guns. But I do agree that a FMJ is probably the best choice anyway. I'll see what happens at the dealer today. Thx... Mike...

 

[rcmodel]

If you are not sure:

Color a round with a black Magic-Marker, force it into the chamber, then remove it.

Where the shiny clean brass is, is what is tight where.

rc

 

[christcorp]

Thanks for the suggestion RC. The more I look at the ammo, and my buddy's advice; I really do believe it is the crimp. It's just a pubic hair, so i have to believe that maybe it wasn't crimped tight enough. I can't believe the bullet is too big. But if you look at the side of the shell, you can see where the bullet stops. Almost like a bulge. More like an imprint of the bullet behind the brass.

So, after work, I'll go back to the dealer and see if I can find a box from a different lot number. If I can, I will try it there. If good, then great. I'll let the dealer know to contact Corbon. If it doesn't work, I'll write it off as a manufacturer that this particular gun doesn't like. It won't be the first. later... mike....

 

[christcorp]

I took the corbon ammo back to the dealer and he also had a look at it. The problem seems to be that the hollow point bullet used by Corbon is a very straight walled design; as opposed to a taper that most FMJ and and other HP have. As such, the bullet wasn't seating like it should and was grabbing the rifling too soon. With some experimenting, we could see the marks on the bullet. Apparently with this gun, the rifling comes back to a point where if the bullet, especially hollow point, is more straight walled, it can't go in far enough with out the sides of the bullet being caught by the rifling.

Federal Hydra-Shok seems to fit fine. The bullet seems more tapered. I haven't had a chance to look at the Fiocchi in that caliber. Most of the FMJ ammo seems to have about a 905 fps and 129 ft/lb spec. The S&B FMJ is closer to 1000 fps and 175 ft/lbs. And for Hollow Point, the Fiocchi is 1100 fps and 205 ft/lb. The fiocchi FMJ seems to be a good compromise with 1000 fps and 155 ft/lbs. So it looks like I have some decent selections.

My other 32acp didn't have this issue, so it's either this particular gun or the ammo design of corbon. I've read a lot of articles about military style handguns that don't do well with certain HP type ammo. Especially those that don't taper. Thanks for the input. later.... mike....

 

[Badger Arms]

HA! I win. The "Throat" of the chamber is actually the rear part of the barrel, proper, where the rifling is relieved to allow the bullet to enter the barrel but not be touching the rifling yet. This is actually the only significant difference between a Mil-Spec 5.56x45mm chamber and a .223 Remington chamber. At any rate, SAAMI specs, those that CorBon chooses to follow, and Cold War manufacturing tolerances stacked up against you... but really interesting that your FEG has such a short throat. Wonder how my CZ 82 is? My Makarovs? Hmmmm.

 

[christcorp]

FWIW; I tried 6 different ammos at the shop. Only the corbon had the problem. Magtech, lawmen, american, hydra-shok, blazer, and winchester all did fine. If I wanted to, I could have the chamber bored to saami, but it's a lot cheaper to use a different brand of ammo.