Tight Throat in 40 XDM?

[happy7]

Earlier this year I bought a 40 Xdm In another thread I have talked about my leading issues with this gun, which I think in part is due to the shallowness of the rifling.

But my question here is that I loaded op some of Lee's 175 grain TC bullets to an overal length of 1.13, meaning that about .04 of the bullet was sticking out past where the taper of the truncated cone starts. But cartridges loaded like this would not chamber reliably. I found that only when I seated the bullets flush to the shoulder where the cone started, (OAL of 1.09) that it would chamber easily. By "chamber", I mean "fully chamber". That is the cartridge would not fully enter the chamber. Feeding itself was not an issue. This means to me that the barrel has a very tight throat. The XDm does come standard with a match barrel. So is this normal? I don't have nearly as much experience with autos, as with revolvers loading cast, but do load for 45 auto and 9mm, also truncated cone designs and have never had this problem before. But I would appreciate input from those of you with more experience.

Sized .401 and lubed with speed green.
Sized bullets do measure .401 to .4015
Barrel slug measures .40025 or so. I mean a quarter of a hash past .400 on the micrometer.

[herb101]

My 40 Cal glock is the same way , but it is a sub. comp. TC loaded past the taper will not let the chamber close and the rounds were not past max case length.

[Echo]

Happy7, do you mean that the round will not chamber when stripped from the magazine in normal operation, or will not chamber in the dis-assembled barrel? A .040 proud boolit should cahmber in normal operation - I theenk...

[happy7]

Even in the disassembled barrel it will not chamber.

[happy7]

I sized some bullets at .400 and they seem to function well. I am going to give them a try at the range in the next couple days.

I sure would like to hear from others who have an XDm in 40 to see if this is "normal".

[happy7]

Well, the bullets sized to .400 and seated normally functioned 100% so that problem is solved, but I still think that it is a bit strange that .401 sized bullets will not chamber. Here is a target I fired. I am not very happy with the group yet, but I have come a long way with this gun from not being able to even hit the target. Now that it functions reliably, I can work a little on load developement and try to shrink this group more.