PP gas cutting

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kwilliams
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PP gas cutting

Post by kwilliams » Mon Mar 15, 2021 4:21 pm

These 2 pics show what just happened in my 45-90 by seating bullet in the case at .130" deep over a .03" ldpe and a .03" veggie below it. Been getting paper rings and so trying different case lengths and seating depths. This load & case length had no paper rings, but serious bullet damage. Using a .444 dia. 450 gr. money bullet wrapped to .450 dia. with .002 paper, neck sized brass and slip fit of bullet. Chamber was cut with a Clymer 45-90 win. reamer, a chamber cast does show anything out of ordinary except for being generous in the neck dia. Been experimenting with loads for 3 weeks, do get some fine 200 yd 5 shot groups and then randomly I will be pushing lead from bore. Thoughts?
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VectorMan
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Re: PP gas cutting

Post by VectorMan » Mon Mar 15, 2021 4:31 pm

What is your lead mixture?
What powder charge?
"keep adding powder til it bloodies your nose and blacks your eyes, then back it off bout 5 grains."

VectorMan
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Re: PP gas cutting

Post by VectorMan » Mon Mar 15, 2021 5:03 pm

Show a picture of your wrapped bullet and your chamber casting.
"keep adding powder til it bloodies your nose and blacks your eyes, then back it off bout 5 grains."

kwilliams
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Re: PP gas cutting

Post by kwilliams » Mon Mar 15, 2021 5:06 pm

16:1 alloy, 88 grns. of Swiss 1 1/2f. Tried a deeper bullet seat at .250, no gas cutting there but the occasional paper ring or blown patch with the resultant leading.....there's goes that group. Wondering out loud if a dual diameter bullet would work better in a less than desirable chamber?
kw

kwilliams
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Re: PP gas cutting

Post by kwilliams » Mon Mar 15, 2021 5:08 pm

will post chamber cast and wrapped bullet pic.
kw

Kurt
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Re: PP gas cutting

Post by Kurt » Mon Mar 15, 2021 5:15 pm

Measure the inside of the fired case to check if the wads are wider diameter than the inside case neck.
If the wads are smaller than the inside the fired case mouth that would be some of your problem.
The reason a dog has so many friends is because he wags his tail instead of his tongue.

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Kurt
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Re: PP gas cutting

Post by Kurt » Mon Mar 15, 2021 5:22 pm

Also,
If your sizing the necks down with a bullet seated you are also compressing the wad diameter. The gas will bypass the wad/wads before they expand and seal the space in the throat.
The reason a dog has so many friends is because he wags his tail instead of his tongue.

"Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery"Winston Churchill

kwilliams
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Re: PP gas cutting

Post by kwilliams » Mon Mar 15, 2021 5:29 pm

Kurt
my neck sized id is .451"+ the wads are .463", they seem tight and are firmly in place.
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kwilliams
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Re: PP gas cutting

Post by kwilliams » Mon Mar 15, 2021 5:31 pm

Not sizing with bullet in place.
kw

VectorMan
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Re: PP gas cutting

Post by VectorMan » Mon Mar 15, 2021 5:33 pm

Where did your alloy come from?
"keep adding powder til it bloodies your nose and blacks your eyes, then back it off bout 5 grains."

semtav
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Re: PP gas cutting

Post by semtav » Mon Mar 15, 2021 5:51 pm

Kim
I'd make a wild venture that it might be that free bore that's giving you a little problem. A dual diameter as long as you have it up into the free bore or a groove diameter might be better. I've got some I should have sent with you the other day.

(Incidentally, Kim kicked our butts with his new 45 2 7/8 at the Buffalo Match Saturday)

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bpcr shooter
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Re: PP gas cutting

Post by bpcr shooter » Mon Mar 15, 2021 5:59 pm

how short of chamber length is your brass? I run mine .002-.003 short and get no rings....ever. I also dont measure from the bottom of the base, measure from the top of the base, to case mouth, as rim thickness can vary. I adjust as necessary.

Have you tried a .060 poly wad?

How are you controlling fouling? Are you sure your chamber and barrel is dry?

Have you tried seating only .080? If its for target work only that should be plenty to hold the bullet.

its almost as if your bullet is not obturating very much. From your pics, there is very little rifling marks. 16-1 should be just about perfect for your load, IF its truly 16-1. It may be time to change up to a DDPP bullet too, no more sizing, and you will get a better seal as the bullet is the size it needs to be from the get go.

Sorry for all the ???'s

Matt
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Kurt
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Re: PP gas cutting

Post by Kurt » Mon Mar 15, 2021 6:29 pm

That is a bunch of free bore.
With that much free bore the groove or close to groove diameter would help.
I had a rifle with a chamber like that and the groove diameter improved the results quite a lot.

I like your bullet design!!
Last edited by Kurt on Mon Mar 15, 2021 6:30 pm, edited 1 time in total.
The reason a dog has so many friends is because he wags his tail instead of his tongue.

"Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery"Winston Churchill

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Don McDowell
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Re: PP gas cutting

Post by Don McDowell » Mon Mar 15, 2021 6:29 pm

.446 or larger bullet before patching will likely stop the skid marks on the side of the bullet.
AKA Donny Ray Rockslinger :?

kwilliams
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Re: PP gas cutting

Post by kwilliams » Mon Mar 15, 2021 6:40 pm

Yes tried .060 poly and saw some case stretching so went back to .030" poly-veggie stack. Started with long brass based on cast length but that rolled in the throat on firing and of course had rings and poor accuracy, kept trimming by .003 increments, now at 2.415" and at least they showed no paper pieces.

Brian I may have to come see you and "borrow" a few DD slugs!

kw

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