Slip fitting with unfired brass

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srkmarine1101
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Slip fitting with unfired brass

Post by srkmarine1101 »

Hello folks. Im getting ready to start loading for a new 45-90. Rifle is a C. Sharps 1874. I'd like to slip fit my bullets. Plan is to shoot my bullets as cast at .458.

From my understanding, after FL resizing my new brass I will need to use an expander die (Buffalo Arms?) to ensure neck tension is consistent and is just enough so bullets can be slip fit.
How much neck tension are you guys using?
Any idea as far how much I should start with?

Thanks!

Shaun
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Lumpy Grits
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Re: Slip fitting with unfired brass

Post by Lumpy Grits »

Anneal your case necks.
Check your case length.
Try a .459 expander.
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Re: Slip fitting with unfired brass

Post by Coltsmoke »

If you are slip fitting bullets you have 0 neck tension. If you take a case that is .457 and force a .458 bullet into it, you have .001 neck tension. Do as Lumpy said.
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srkmarine1101
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Re: Slip fitting with unfired brass

Post by srkmarine1101 »

Makes sense. Thanks much!
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bpcr shooter
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Re: Slip fitting with unfired brass

Post by bpcr shooter »

If it were me....I know its not but, I would fire form my brass, measure it, then purchase a bullet that will slip fit in that case. Taper crimp enough so the bullet can still move but not fall out. Your bullets may be small at .458 and that may get you some gas cutting, if possible, send one into the berm and try to find it, look at the base of the bullet, it should be nice and square, no little chunks or mouse bites out of it.

matt
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srkmarine1101
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Re: Slip fitting with unfired brass

Post by srkmarine1101 »

bpcr shooter wrote: Mon Nov 28, 2022 6:59 pm If it were me....I know its not but, I would fire form my brass, measure it, then purchase a bullet that will slip fit in that case. Taper crimp enough so the bullet can still move but not fall out. Your bullets may be small at .458 and that may get you some gas cutting, if possible, send one into the berm and try to find it, look at the base of the bullet, it should be nice and square, no little chunks or mouse bites out of it.

matt
I never considered this. Thanks Matt.
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desert deuce
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Re: Slip fitting with unfired brass

Post by desert deuce »

The Chamber of the rifle is the heart and soul of the rifle. Not the barrel, not the case and not the bullet.

To begin: Recommend using a new unfired case. Preferably Starline in a .45 Caliber as they come closer to standard chamber lengths.
Anneal the case about one inch down from the mouth and make sure the mouth of the case is annealed as this is where most problems begin.
Make sure case is no longer than 2.40 inches long if a 45-90, 2.10 if a 45-70.

Use a good quality bullet, either 1-20 or 1-16 alloy, whichever you intend to use and ensure it is in fact .4580" in diameter at the base band. If you don't have a micrometer you can use a good quality dial caliper but this measure is critical.

Prime the case any old primer. Drop in about 8 grains of pistol powder (I use WW-231) in the bottom of the case. Fill case with highly compressed cornmeal, top with card wad. Chamber in rifle and fire into the air with back to wind.

You should now have a case fire formed to that rifle's chamber. Measure the length (must be 2.40" or less), debur the inside mouth of the case, see if the .458 bullet will slip fit into the mouth of the case base first. It should. If not, prime the case again any primer, any black powder to the height you compress it about 0.10" push bullet in so it will chamber, (may have to compress more), to get the round to chamber.

Fire this one round into the dirt, bank, etc. Clean the inside of the case with something like a test tube nylon brush, deburr inside mouth of case, see if .4580 bullet will now slip easily all the way in to the mouth of the case base first. If not, check length and if over 2.40" and or a slight crimp at mouth of case the chamber is probably too tight and should be opened up until it no longer stretches brass and will allow a sized .4580 bullet to slip in and out the mouth of the fire formed case.

I have not encountered a chamber that is too short for the caliber but I guess it could happen.

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Re: Slip fitting with unfired brass

Post by Coltsmoke »

DD, it is easy to see you have read my book. :wink: :lol: :lol:
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srkmarine1101
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Re: Slip fitting with unfired brass

Post by srkmarine1101 »

You guys are awesome. Thanks for all the great info.
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Re: Slip fitting with unfired brass

Post by srkmarine1101 »

bpcr shooter wrote: Mon Nov 28, 2022 6:59 pm If it were me....I know its not but, I would fire form my brass, measure it, then purchase a bullet that will slip fit in that case. Taper crimp enough so the bullet can still move but not fall out. Your bullets may be small at .458 and that may get you some gas cutting, if possible, send one into the berm and try to find it, look at the base of the bullet, it should be nice and square, no little chunks or mouse bites out of it.

matt
Once you have your measurements from that initial piece of fireformed brass, and you've confirmed bullet diameter, I am assuming you'd then need to fireform the rest of your brass in a similar fashion to what desert deuce mentions below?
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Re: Slip fitting with unfired brass

Post by gunlaker »

I do it a little differently, but end up with basically the same thing. I have a lot of molds so I usually fireform with bullets, unless I'm forming some oddball brass.

It's pretty unlikely you'll need to full length size your Starline brass to get it to chamber, chances are very good that it'll slip right in. I'd anneal them, and use the largest diameter bullets that slip into the case. Probably it'll be more like 0.459" if I had to bet.

After shooting and annealing them again, they'll be pretty close to stabilized. Then you'll know how big a bullet you'll need to get a good ( not loose or sloppy ) slip fit bullet.

I like slip fit, but I'd also had some pretty outstanding results with 0.001" neck tension, although it's more work. If the rifle shoots well with slip fit bullets that's generally a good thing. As far as seating depth, a good place to start is having the bullet engraving the rifling lightly upon chambering. I start with 1/2 of the first driving band engraved. I rarely find an increase in accuracy by changing that, although it can happen :-)

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desert deuce
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Re: Slip fitting with unfired brass

Post by desert deuce »

Something I probably should have mentioned earlier especially for .44 & .45 rifle brass. 40 seems to be a different matter a bit.

New brass and even fireformed brass come into this category of from various factors end up with slight collapsing, denting, enlargement, etc at the mouth of the case. No particular cause, it is just a characteristic to be alert for.

I use and inside case neck expander at .458 for a .45 and deburr the mouth of cases to make them round after annealing and after tumbling if the bullet is too tight slip fitting or won't go at all.

I check new and fireformed brass for enough annealing by squeezing with fingers the mouth of the annealed case. If it compresses to an oval and does not spring back that is enough annealing in my mind. If it springs right back to round it gets more annealing. It is possible to over anneal though.

With these larger capacity cases I seem to get much longer case life than sized cases and the last thing I want during a match while on the clock, or anytime for that matter, is a separated case stuck up in the rifling. I hear some use a neck only sizer to obtain neck tension by using a neck only sizer but I have not travelled over that trail yet and so far do not see the need to.
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Re: Slip fitting with unfired brass

Post by bpcr shooter »

srkmarine1101 wrote: Thu Dec 01, 2022 8:06 pm
bpcr shooter wrote: Mon Nov 28, 2022 6:59 pm If it were me....I know its not but, I would fire form my brass, measure it, then purchase a bullet that will slip fit in that case. Taper crimp enough so the bullet can still move but not fall out. Your bullets may be small at .458 and that may get you some gas cutting, if possible, send one into the berm and try to find it, look at the base of the bullet, it should be nice and square, no little chunks or mouse bites out of it.

matt
Once you have your measurements from that initial piece of fireformed brass, and you've confirmed bullet diameter, I am assuming you'd then need to fireform the rest of your brass in a similar fashion to what desert deuce mentions below?
correct!!
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Re: Slip fitting with unfired brass

Post by desert deuce »

Now Matt, you might want to go back through your last post and think through what you wrote step by step.
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Re: Slip fitting with unfired brass

Post by bpcr shooter »

ok...I give, whats wrong with it?
.

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