Feeding issue with cast TCFP and 40 S&W

[Sin City Shootist]

I don't remember having this problem with my last batch, but this almost cartoonish. Have you ever watched a dummy try to carry a 2x4 through a door sideways, or a dog trying to bring a big bone through a doggie door sideways? Well that's whats happening with these loads. The nose of the bullet is jammed into the top of the breach and the case head partially in the mag(vertical). It does it once or twice in almost every mag. Factory loads feed fine.

col 1.125 and even set them to 1.100 as listed in Lyman 49. they fire and eject fine. Could this be a crimp problem?

Oops, almost forgot, this is an FNP-40

 

[243winxb]

My guess is>Your using a hotter load then factory? The case head is slow sliding up the bolt face. Maybe taking to long to get under the extractor. Or your magazine needs a slight adjustment, close the lips a hair.

 

[Sin City Shootist]

They Chrono'ed at 1040fps(first time out with a chrono) but that was after I shortened them down to 1.100. I did bring some Federal cheap stuff out and they were 949. The load data was under max, 5.4 Universal.

Think they are to hot?

 

[rcmodel]

Need to know the exact make & model bullet you are using.
Lyman lists three TC cast bullets.
150 grain #401654 seats 1.090".
175-180 #401043 seats 1.125".
175-180 #401638 seats 1.100".
The difference in TC ogive shape of each one determines the OAL that will feed right.

I'd be guessing, but maybe you got some different bullet design with a very short TC ogive, and it is hitting the top of the chamber before it can pop up out of the feed lips and toggle on over into the chamber.

Also need to know what powder & charge you are using?
As 243winxb mentioned, slide cycle speed with a very fast powder or hot load might cause the slide to outrun the magazine spring.

rc

 

[Peter_S]

If there is a crimp issue, are you seeing any kind of "ding" on the casing that might indicate that the rim of the case is hitting the feed ramp and causing the round to rotate too far before it enters the breech/chamber?

 

[Sin City Shootist]

Missouri bullet IDP #5

 

[243winxb]

Check that the case heads rim diameter fits in the bolt face. If to wide the case head/rim drags sliding up the bolt face.

 

[Sin City Shootist]

If there is a crimp issue, are you seeing any kind of "ding" on the casing that might indicate that the rim of the case is hitting the feed ramp and causing the round to rotate too far before it enters the breech/chamber?

I haven't noticed any but I will look at some brass when I get home.

 

[243winxb]

Missouri bullet IDP #5 180gr. for .40 S&W/10mm

Nice looking bullet

 

[Sin City Shootist]

Check that the case heads rim diameter fits in the bolt face. If to wide the case head/rim drags sliding up the bolt face.

Will check tonight as well.

 

[rcmodel]

Take the barrel out of your gun to use as a chamber guage.
Seat as long as you can without the bullet hitting the rifling leade when you drop one in the chamber.

Longer OAL should get pushed down by the bullet hitting the top of the chamber sooner.
That in turn will get the case rim up before the round gets caught by the slide.

The load data was under max, 5.4 Universal.

4.7 Universal is Start, and 5.4 is MAX with the single grease groove BB Lyman mold.
It is very similiar to the MB bullet you have.

5.5 is MAX with the two-groove flat-base Lyman bullet.
Might try backing off a little, but only after you try what I said about seating as long as you can.

rc

 

[Sin City Shootist]

I read that thread earlier about doing that RC. I will definitely do that tonight.

 

[243winxb]

RC posted while i was typing.

The load data was under max, 5.4 Universal.

Think they are to hot?

Hard to say, unless someone has printed data for lead?? Hodgdon has a max of 5.8gr with a 180 Jacketed bullet. Drop back on the powder charge next loading to match factory 180 velocity, see what happens. The slide speed may get slower and give the round time to get out of the magazine. Have you tried a different magazine?

 

[Sin City Shootist]

Yes, does it with all 3 mags.

 

[Sin City Shootist]

Update, I can lengthen them longer then the mag without getting into the lands. I'm going to play around with seating depths to see if I can get it to cycle properly.

 

[Sin City Shootist]

Running longer fixed the problem. Three mags cycled perfectly, and chrono'ed out at 850fps - 905fps. So I guess the question remains, were they too fast or was it a length problem.

 

[rcmodel]

It was a length problem I betcha.

rc

 

[dwhite]

What is your overall length now?

Inquiring minds......


All the Best,
D. White

 

[Sin City Shootist]

1.175, I'm considering going back to Clays for the powder too as I can keep the pressure on the back of the bullet for expansion without going too fast and leading the barrel.