New Colt Cobra target reloading problems

[brutus51]

It appears the chambers of my new Cobra target have been bored short.
It won't chamber my favorite 158gr. semi-wadcutter load.
Reloads work fine in my 45 year old Python and my Dan Wesson.
Anyone else experiencing this problem?

 

[Jesse Heywood]

I've put about 200 357 rounds through mine with no problem. Before you call Colt try chambering sized brass. If that works you likely have a problem with a bulge from seating or crimping. Paint the neck with a marker and see what interferes. If the brass doesn't chamber, measure and check the length, should be 1.290 max. You can also check the chamber depth with your caliper. Should be 1.239 - 1.249. Dimensions are shown at SAAMI.org. Here's a copy.

 

[brutus51]

Found out that if I don't apply any crimp the rounds will slide in with no problem. As a result I purchased a Lee factory crimp die, which arrived in the mail yesterday. Tried it this morning and now all my reloads work perfectly. Wondering if anyone else has experienced this.

 

[joneb]

I trim revolver brass to the same length this will prevent bulging on a longer case.
With a Lee FCD it may resize the bullet, if a lead bullet is .358-.359" along with thick brass and the bullet is sized down and it will decrease case neck tension on the bullet. For bullets that are .358 or larger I like R-P brass.
I use the Lee collet crimp die (same as FCD but no sizing ring) for plated and jacketed if a roll or taper crimp is not sufficient to keep the bullet from being pulled out of the case from recoil.

 

[FROGO207]

Yeah I would see if your bullet will push throug the throat before anything else. Your FCD may be post sizing the bullet so it fits a small sized throat and then works. Look for leading in the barrel and at accuracy if this is the case. May have to get your cylinder reamed if this is the case.

 

[Walkalong]

Found out that if I don't apply any crimp the rounds will slide in with no problem.

Then you were over crimping them and bulging the case just below it. The FCD merely squished the mistake to fit.

 

[Jesse Heywood]

Then you were over crimping them and bulging the case just below it. The FCD merely squished the mistake to fit.

Agreed. You were applying to much crimp. The squeezed brass has to go somewhere, and expands the case. usually just below the bullet. Walkalong has a lengthy thread on crimping, with a lot of photos to show the proper crimp. The FCD simply masks the problem.

 

[rfwobbly]

I've been going through this with 38Spcl loads using DEWC. Two in every 50 bulge at the base of the seated bullet. Bulges larger than 0.380" won't chamber.

 

[brutus51]

I agree that is what is happening, although I was applying a very light roll crimp with my RCBS dies, again never had a problem with my Python, Dan Wesson or Colt agent in 38 special.. Only time I apply a heavy crimp is with full house magnum loads. In this case I reloaded Lazercast 158gr SWC at .358Ø
these were most problematic, extreme 125gr. plated flat point at .357Ø and some Meister 158gr SWC at .357Ø.
50 extreme plated bullets with no crimp applied fit smoothly with no problem. After receiving the Lee die I applied a crimp to those rounds with no problems.
The .358Ø Lazercast bullets will not pass freely through the throats of the Cobra.
Didn't have any bulges in the brass but cases measuring .378Ø at the case mouth won't go.

 

[FROGO207]

measure one after it has been run through the FCD. It will be smaller. Bet you will have to open up the throats or always use FCD with that revolver when using lead bullets. If you get no leading I would just use the FCD for it's ammo and call it good.

 

[Eddietruett]

With only one here and there doing the bulging, my guess is your bullets are not consistently sized.

 

[Jesse Heywood]

In January I gauged 3 of my Colts. Was surprised at the variation in chamber sizes. You can measure inside diameter with a set of ball gauges and your mike and/or caliper with a set similar to this.
https://www.amazon.com/Belloc-Teles...words=ball&qid=1586140119&s=industrial&sr=1-1
SAAMI specifies chamber .3809-.3849, throat .3580-.3620.

Chamber & throat diameters.
New King Cobra - .378 / .357
Diamondback - .382 / .358
New Cobra - .384 / .356

Also SAAMI the case diameter is .379-.383

 

[rfwobbly]

With only one here and there doing the bulging, my guess is your bullets are not consistently sized.

If you're talking about my 38Spcl loads...
No sir. In fact it's the brass. Some brass simply won't except Wad Cutters loaded that deeply into the case. PMC seems to be one of the big offenders. I'm weeding them out as I find them.

 

[ATLDave]

I've been going through this with 38Spcl loads using DEWC. Two in every 50 bulge at the base of the seated bullet. Bulges larger than 0.380" won't chamber.

View attachment 905736

Seems more likely that bulge is a function of varying brass thickness than crimping.

 

[brutus51]

measure one after it has been run through the FCD. It will be smaller. Bet you will have to open up the throats or always use FCD with that revolver when using lead bullets. If you get no leading I would just use the FCD for it's ammo and call it good.

Think that's going to be my game plan for all my .357 reloads. I always crimp separately anyway so it's not an imposition.

 

[FROGO207]

Just test and make sure you do not get leading or loose accuracy because of the post sizing though. Or use plated bullets, they will be smaller in diameter and more likely to chamber without need for post sizing. It is a cost thing mostly but not a big differenct to some that don't want to have that extra press pull and any possible loss of accuracy. Your call ultimately.

 

[Eddietruett]

I've been going through this with 38Spcl loads using DEWC. Two in every 50 bulge at the base of the seated bullet. Bulges larger than 0.380" won't chamber.

View attachment 905736

If you're talking about my 38Spcl loads...
No sir. In fact it's the brass. Some brass simply won't except Wad Cutters loaded that deeply into the case. PMC seems to be one of the big offenders. I'm weeding them out as I find them.

I've never encountered that situation. I've always just cleaned my .38 brass and loaded away. I load about 10k wadcutters a year and probably have a hundred different brands of brass. Maybe I've never had any pmc brass. It would be hard to believe I've never had any as many as I go through, but its possible. I had a primer seating problem one time with my Dillon 650 that I thought I had narrowed down to 2 different brands of brass, but the problem got worse and all brands of brass started having problems. Turned out to be a problem with my press. One will adjustment and the problem has go away for ever I hope. I do use a Lee seating Die and a Lee Factory Crimp Die. They do little resizing when seating and crimping. Maybe that is why I've not run into your problem. Good luck solving your problem. I've been loading over 40 years and just when I think I've run across every problem that you can imagine, a new one pops up. You did the right thing. Throw it out to a crowd. Odds are someone will know the cure.

 

[rfwobbly]

I do use a .... Lee Factory Crimp Die. They do little resizing when seating and crimping. Maybe that is why I've not run into your problem.

The FCD is why you haven't seen the issue. It's busy ironing out any irregularities in the case wall.