shortening a bullet mold

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Perentie
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Location: Queensland, Australia.

shortening a bullet mold

Post by Perentie »

I am playing with a .40 cal using a full length .405 win case. Shall we call it a .40-2.6. I had the reamer made to suit that shell and seat bore diameter PP bullets. I realise I am not shooting long range yet, but I chose the Jim 396-415E mold. Wrapped with the paper I have it hand seats and chambers nicely .
I cant get Swiss any more and the Wano PP I am using now gets me around the 1350 fps. Thats with a case full compressed with a poly wad 12 thou.
The barrel is 16 twist and this bullet is 1.42 long with a .620 nose.
An article by Texas Mac suggests this is too long for under 1400 fps and that 1.360 is better.
I am thinking that I could chuck the mold in the 4 jaw and machine a few thou off without a problem as the body length is a fair bit longer than the nose.
I was comparing this with the Jim 395-410E which is 1.44 long with equal nose and body length of 0.72 each
This lets me believe I could get my bullet under 1.4 inch and have a body of 0.78 and remain with a nose of 0.620 and be stable at say 1000 yds with my 16 twist and current MV
Does this sound feasible?
Coltsmoke
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Re: shortening a bullet mold

Post by Coltsmoke »

Have you shot it like it is to see if it works? If not, I would do that first. If not satisfied, cut it to 1.400 then try it. You can take more off later if you want to, but you can't put it back.
Normal isn't coming back, but Jesus is.
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Distant Thunder
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Re: shortening a bullet mold

Post by Distant Thunder »

As Colt suggests, it's not a bad thing to sneak up on the optimum length. That being said, when I look at the numbers my estimate of the optimum length given your twist and velocity would be 1.330 to 1.340".

You would still have a nose length around 46% of the OAL. That is a little longer than I like but does not mean it won't still shoot well in various conditions.

There are other things that are in play besides the twist, OAL and velocity and the only way to know if it will work satisfactorily at a shorter length is to try it. If it were me I would not hesitate cutting it shorter and Colts' 1.400" would be a good start, then see how it does. The drawing that BACO shows for that bullet doesn't look really pointed and that will be a good thing with a shorter OAL.

Understand that I own very few molds that I have not modified in some way. Some showed improvement and others not so much. I enjoy experimenting and I learn something either way.

Whatever you decide to do, please let us know how it worked out.
Jim Kluskens
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desert deuce
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Re: shortening a bullet mold

Post by desert deuce »

Hearing rumors of a 40-82 developed with reduction in recoil in mind, 14 twist Douglas Barrel using 460-475 grain bullets shooting really well at distance to 1,000 yards.
But, the reduction in recoil was negligible over the larger calibers.
I remember watching a shooter at Lodi a couple of years ago with a 40-65 do really well at 1,000 yards, I think he said it was a 16 twist bbl.
Sometimes you get the chicken, and sometimes you get the feathers!
Kurt
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Re: shortening a bullet mold

Post by Kurt »

One thing to keep in mind when shortening a mould is pay attention where the vent line is. Don't get too close to the vent line, it can make a wide chip if the edge breaks off on the base and it will show up on the bullet base edge like flashing.
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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Distant Thunder
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Re: shortening a bullet mold

Post by Distant Thunder »

What's it been now, about 25 since the .38s and .40s were going to take over Creedmoor? Not sure if that ever happened or not? In the places I shoot the .45s still seem to dominate and most recently the .45-70 with paper patch bullets over 82 or so grains of 1 1/2 Swiss. It's all very interesting how things go.
Jim Kluskens
aka Distant Thunder
Kurt
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Re: shortening a bullet mold

Post by Kurt »

Distant Thunder wrote: Sat Dec 11, 2021 12:41 pm What's it been now, about 25 since the .38s and .40s were going to take over Creedmoor? Not sure if that ever happened or not? In the places I shoot the .45s still seem to dominate and most recently the .45-70 with paper patch bullets over 82 or so grains of 1 1/2 Swiss. It's all very interesting how things go.
Jim,

From what I have seen with Arnie's .40 and .38-50 is capable of convinced me making a .38-50. If it falls short for the 1K I know it will do just fine for those iron critters halve that distance.
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
Perentie
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Joined: Mon Jul 21, 2014 9:22 am
Location: Queensland, Australia.

Re: shortening a bullet mold

Post by Perentie »

Thanks for the replies and hints.
I have got it to shoot quite well (by my standards) using the last of my Swiss, out to 400 yds.
Now I have to start load development again with Wano that has less grunt.I would like to get to a range that will let me shoot to 1000 one day so I dont want to waste primers powder and lead getting a load that only shoots to 600 or so then gets unstable.
The advice from Wayne and DT leads me to give it a go anyway. :)
Our club had three BPCR shooters but the other two have given it away. One with health issues and the other age (93). We three shot in the World Creedmoor Assn Match in Brisbane in 2006 against NZ and USA. There has been no more since then here.
Our constitution makes it difficult for me to come and shoot on my own as I have been for the last 20 years ( I am an R.O.) and no nearby ranges shoot BPCR.
A couple of our NSW members on here are in the BRAA. Buffalo Rifle Assn of Australia. I would like to get down to NSW and shoot with them when this Border nonsense eases up.
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J.B.
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Re: shortening a bullet mold

Post by J.B. »

G'day Perentie. It goes without saying that you are always welcome to join us if and when you can. We'd love to see you. The tyranny of distance hasnt been aided by the 'Covid Tango' of the last two years and I dont think the dance is over yet but the invitations stands. Cooyal near Mudgee is our most used facility but even that has been hard to get to for us.. let alone Queenslanders ! Our other range is at Nioka, close to Gunnedah. We can get out to 1100+ yards there but the lack of feedback from fall of shot is notoriously frustrating at times. That range is good for three shoots a year ( when we are allowed to do anything :roll: ) with Cooyal making up the balance. Some camp in the clubhouse or commute from Mudgee when they come. As for moulds.. I've done no adjustments to mine as I've not the skills or gear..but it has meant I've done my best to keep a selection of U.S. and Canadian based mould makers busy and have more than one shelf of moulds to prove it :wink: . Drop us a line and we'll add you to the emailing list to see if we can entice you down. We talk better than we shoot..but we do both :lol:

regards.. Gavin/ J.B.
"an experimental weapon..with experimental ammunition ? ...Lets experiment "
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