Short Chamber in XDM 9mm

[gmantwo]

My XDM 9mm seems to have a very short chamber. If I load the rounds over 1.036 they will not eject loaded, this is with 125 grain Precision bullets. The round will actually separate when you try to eject a loaded round, leaving the bullet stuck in the rifling. Any longer and the gun won't go into battery. Right now it's not a big deal, I've got several thousand Meister 123 grain lead bullets that require me to load them to 1.022 in order to fully cover the lube groove. When I'm done with these bullets and start shooting the 115mg's I shoot in my open gun, or go to a longer, heavier bullet I'm thinking of having the chamber reamed deeper so I can load to one OAL for both guns. Not sure about that yet.

[scap99]

Yes, I hate how short the freebore is in my XDM.

I am severely limited in how long I can load my 9mm ammo because I use this pistol from time to time.

[Pat Miles]

Make sure the longer rounds will fit in the mag before you ream the chamber deeper.

CYa,

Pat

[dbxdm9]

"ream" the chamber?

I have the same gun, and have reloaded ammo up to 1.160 with no problems. SAMMI spec is 1.169 for 9mm. You think your gun needs modified to make that work?

What am I missing?

[calishootr]

its not ream the chamber per say....its increasing the leade or distance from the chamber to the actual rifling, for most, its a matter of changingthe bullets, different bullet profiles will sit deeper into the leade...like in my limted gun the leade is cut really long i can load out to 1.200, where the 'standard' .40 i think is 1.135???

[gmantwo]

Yes, I mistated that, I won't change chamber depth, I'll give more room for the bullet depth. When I go to a 147 grain bullet, they will have to be loaded very deep in the case the way the gun is now and I'd rather be able to load all my 9mm to 1.158 or so. Even with 125 grain bullets that's not possible in this particular gun as it is. 9mm headspaces on the case mouth and I certainly don't want to change that point in the barrel.

[GlennRasch]

My XDM 9mm seems to have a very short chamber. If I load the rounds over 1.036 they will not eject loaded, this is with 125 grain Precision bullets. The round will actually separate when you try to eject a loaded round, leaving the bullet stuck in the rifling. Any longer and the gun won't go into battery. Right now it's not a big deal, I've got several thousand Meister 123 grain lead bullets that require me to load them to 1.022 in order to fully cover the lube groove. When I'm done with these bullets and start shooting the 115mg's I shoot in my open gun, or go to a longer, heavier bullet I'm thinking of having the chamber reamed deeper so I can load to one OAL for both guns. Not sure about that yet.

Have not had any problem's with my sons......... xdm / 9mm

[Marv Z]

I load all my 9mm to 1.135. That includes 124gr and 147gr. No problems at all. Shot 200 rounds yesterday out of my Canyon Creek XDM and ejected lots of live rounds while adjusting the sites. I would contact Springfield or give Rich at Canyon Creek a call. He'll figure it out.

[CGT80]

I load all my 9mm to 1.135. That includes 124gr and 147gr. No problems at all. Shot 200 rounds yesterday out of my Canyon Creek XDM and ejected lots of live rounds while adjusting the sites. I would contact Springfield or give Rich at Canyon Creek a call. He'll figure it out.

I just posted to this same question in a different thread. I had to have my barsto 9mm barrel tapered to accept a longer round. I also had the chamber opened up with a reamer. From barsto it was just way too tight for anything but factory new ammo. I haven't tested mine on paper, but when shooting steel targets in competition I haven't noticed any decrease in accuracy. My reliability went from, not at all, to rarely having a failure. Before having the barrel opened up, my ammo would pass a dillon case gage but would not drop freely into the barrel.

[AZXDM]

In auto's the bullet profile dictates the seating depth. I too load Precision 125's, they have to be seated shorter than what I like but they function fine. I was loading another brand out to 1.125 which gave 100 percent reliability. I think the Precisions are at 1.10 in my gun presently. These are both TC profile bullets. The difference in my two bullets is the shape of the cone. The precision bullet has a "fatter" nose, whereas the other brand the nose would fit into the barrel without contacting the rifling. It just so happened that the amount of bullet in the case is the same, the Precision bullet is shorter. This is a very important point when reloading. If you seat a bullet deeper than before, using the same charge you will increase pressure. This can be dangerous at the worst but will also affect accuracy.

You might try some other bullets before reaming the chamber, see if you can find one you like that works the way you want it too. You could also look into a different barrel with more generous dimensions, then you would still have the stock barrel. Just a thought, hope you find a good solution, let us know.

Best, Rick

[Bansheex]

I noticed the same thing with my 9mm Bar-Sto barrel. I have a Comp on it and am trying to get the loads up in pressure for the comp. I measured the chamber and it's .751 I have to load to a OAL of 1.10 to get the bullet to drop into the barrel. I have not checked the stock barrel yet to see what it it.

[twodownzero]

My M&P is the same way. It won't reliably take 147s loaded beyond 1.120".

[d_striker]

One very basic thing to consider before you do something that can't be reversed. Lead bullets are sized at least .001" larger than your bore. In the case of 9mm, they are at least .356".

I cast the lee 356-124-2r bullet and it runs great. The bearing surface of the bullet is 99% seated in the case so there isn't a chance for it to become lodged in the chamber.

Does reaming affect accuracy at all?

Edited October 12, 2010 by d_striker

[Justsomeguy]

If, upon firing, the bearing surface of the bullet enters the free bore part of the barrel before any part of the bullet hits the lands it should still be going straight enough not to affect accuracy. However, if the free bore is too large (wide), or the chamber too large, so that the bullet might cant slightly, then accuracy may be affected, as an off center projectile will be "mushed" down the barrel onto its flight path. In most instances I don't think this would happen though, especially in a pistol. The ideal situation would still be to get the bullet to enter the rifling while it is still exiting the case in the chamber and before you run out of free bore. Generally you are only going to increase the free bore by 1 or 2 hundredths of an inch in order to leave room for longer OAL's of the loaded cartridge. This should not be enough to put a bullet in "free bore limbo" and allow it to cant out of line with the centerline of the bore.

[Joe4d]

Are you sure you posted the correct OAL measurments ? 1.036 and 1.022 ? At those lengths not even factory ammo would work. Sure you didnt mean 1.136 and 1.122 ? both of which are still kinda short but not unheard of for a round nose lead bullet.

[Bansheex]

I just measured a Rem factory round and the OAL is 1.102 I know that the factory loads are not all the same. The chamber on my stock XDM barrel is .764

I just went back to loading jacketed bullets. I'm going to see if I can increase the OAL from my lead loads.