Year ago I build a P80 PFC9 (serialised, sorry big brother Im not the droid your looking for....) with an Alpha Shooting Sports slide assembly. This is basically a Gen 3 Glock 19 for all practical purposes. While the gun is a tack driver and probably gives my 1911s a run for their money it occasionally malfunctions (can I say "jams"?). Mostly FTF, rarely a FTE. It is otherwise a really fun sweet gun to shoot.
Im not a believer in modifying guns to get to run like they are expected from the factory, so please no recommendations to polish the bubblegum out of the rails and ramp etc.
But being this is a home build its been a very slow crawl trouble shooting which part is the problem child, I occasionally take it out and have fun shooting it till it jams then look at it with a confused face while scratching my head..... but today I may have found my first clue.
A different kind of jam today was a first, a completely locked up feed just before full battery. Im so glad the striker didnt fire it as it happened mid magazine, click no boom. I went to rack the slide but it was locked up tight. The slide was maybe 1/8" or less out of battery and would not pull back. After several tries I had to beat the slide open using the RMR.... oy.
I field stripped the gun and looked things over no clue. I took the jammed Fiocchi round and dropped it in the chamber of the barrel. I took a different brand and did the same and there it was, my clue... the two do not sit the same in the chamber. The Fiocchi sat way high, the Winchester round sat flush.
I set aside the Fiocchi and switched to my Winchester that fit. I did not get a failure until over 50 rnds later a FTE, which is more the usual suspect.
At home I looked up SAAMI spec 9mm and measured. The Fiocci is on the large side but in tol. The Winchester is on the small side but in tol. Its not the ammo.
I'm not a gunsmith and fully admit I dont have a better way to measure the chamber,, Mititoyo calipers ID blade tips I put an estimated .2" inside the chamber measures about .388", minimum is .3913". If I measure deeper in it measures .38", min is .382" (note, the caliper ID blades do fit and measure all the way up to the lands). As a test both of these two rounds fit exactly the same in my factory Sig barrel.
If my chamber is too small this explains my FTF issues.
Now for my questions:
It also might explain very low frequency FTE issues if say a bullet is on the larger size after fireforming?
What do you all think, bad barrel?
If I buy a new barrel, are afermarket "Glock" barrels drop in?
Photos:
Im not a believer in modifying guns to get to run like they are expected from the factory, so please no recommendations to polish the bubblegum out of the rails and ramp etc.
But being this is a home build its been a very slow crawl trouble shooting which part is the problem child, I occasionally take it out and have fun shooting it till it jams then look at it with a confused face while scratching my head..... but today I may have found my first clue.
A different kind of jam today was a first, a completely locked up feed just before full battery. Im so glad the striker didnt fire it as it happened mid magazine, click no boom. I went to rack the slide but it was locked up tight. The slide was maybe 1/8" or less out of battery and would not pull back. After several tries I had to beat the slide open using the RMR.... oy.
I field stripped the gun and looked things over no clue. I took the jammed Fiocchi round and dropped it in the chamber of the barrel. I took a different brand and did the same and there it was, my clue... the two do not sit the same in the chamber. The Fiocchi sat way high, the Winchester round sat flush.
I set aside the Fiocchi and switched to my Winchester that fit. I did not get a failure until over 50 rnds later a FTE, which is more the usual suspect.
At home I looked up SAAMI spec 9mm and measured. The Fiocci is on the large side but in tol. The Winchester is on the small side but in tol. Its not the ammo.
I'm not a gunsmith and fully admit I dont have a better way to measure the chamber,, Mititoyo calipers ID blade tips I put an estimated .2" inside the chamber measures about .388", minimum is .3913". If I measure deeper in it measures .38", min is .382" (note, the caliper ID blades do fit and measure all the way up to the lands). As a test both of these two rounds fit exactly the same in my factory Sig barrel.
If my chamber is too small this explains my FTF issues.
Now for my questions:
It also might explain very low frequency FTE issues if say a bullet is on the larger size after fireforming?
What do you all think, bad barrel?
If I buy a new barrel, are afermarket "Glock" barrels drop in?
Photos:
, IE too close to the sammi spec, those slightly longer rounds won't jive. They are likely getting bullets shoved into the throat. Which could explain your better precision. However that also means things can get stuck. I would say that your COAL differs a from brand to brand but the unshot cases probably are within spec if measured separately. Most companies get in trouble with COAL being wild. Again, a blue sharpie would confirm my crazy rant!
