Utah Guns Forum banner

Slide lock up with new barrel - need GO - NOGO chamber gauge

3K views 3 replies 2 participants last post by  FrankenHollow 
#1 ·
Maybe someone on here can help out.

A FNP 40 was fitted with a new (threaded) barrel. All things are fine and dandy without ammo. However when using ammo, the gun did not go into battery.

I've looked at all outer dimensions and think that I've fitted those to proverbial death. While things go better, I still have no dice loading some ammo. To me it seems that the barrel throat is not cut wide enough, i.e. a "rounder" bullet - thus wider diameter at the throat - gets pushed and this causes the gun to choke. Conical bullets seem to be better in that area - i.e. smaller diameter and better "fit" into the throat.

I've looked at the gauges but don't want to buy them for that one-time use. Anybody has a .40 S&W Go and NO-GO gauge for checking the chamber? I'm in SLC and depending on distance can either swing by during an evening or on the weekend.

thanks for letting me know.

Regards, DinTex
 
#2 ·
I just want to be sure...

You understand that the headspace gauges won't tell you anything about the throat, correct?
They'll tell you if the barrel is headspaced properly, but that's it.

To learn anything about the throat, there are three primary options:
1. Chamber cast.
2. Impact slug. (Like bore slugging, but instead of pushing the lead through the barrel, you put an anvil behind it and strike the slug a few times to get full expansion and a full impression of the throat.)
3. Pin gauges and a lot of measuring.

-----

Did you check to make sure that the cartridges aren't hanging on the extractor? That would be the first thing I would check.
 
#3 ·
Yes, I know that the gauge will not solve my throat problem, but it will confirm my suspicion by eliminating that my chamber is cut too short. At this point I have no issues with empty brass of whatever manufacturer, but do have problem with loaded brass, i.e. it looks as if the point of contact preventing battery is the bullet (my suspicion).

At which point I would then search for a throat-reamer for the caliber - not even measuring, but rather just based on the idea that that bullet is just too fat for that leade and causes a contact. Resulting in either a bullet setback (higher pressure, etc.) or if the bullet is seated tightly, the barrel not locking up.

:) Maybe I should look for a throat reamer straight away and not verify chamber dimensions?

Regards,
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top