Patched Bullet in a .40?

[Loyalist Dave]

So IF I was to get a .40 caliber barrel with 1:48 twist, and used a paper patched, .375 249 grain bullet, do you think it would stabilize as a T/C Maxi-ball would? Maxi-balls don't go that small unfortunately.

Lyman .375 bullet mold
Just because it would be cool to do it and make it work...

LD

 

[Rat Trapper]

It might, would be interesting to see what happens. With a 1-48 twist ya need to pick a short length bullet.

 

[paulvallandigham]

You can always try it and see if it will stabilize. I personally think the bullet is way too long- about twice the length called for in that caliber and ROT. Good luck. :thumbsup:

 

[longcruise]

No, it won't stabilize! For the very longest bullets in that caliber you need to be around 1/16. For that size you would probably need at least a 1/20 or 1/25. That bullet is right around .94 inch long. If you go by Greenhill using a 150 constant it says a 1/25 is the slowest useable twist rate. Greenhill is by no means the last word, but when it shows you that much diff, it's dang near 100% predictive.

Guys shooting these guns with slugs are inclined to use a 120 constant in Greenhill. That calc suggest a 1/20 as the slowest twist workable.

Barrels in that twist can be purchased and could probably be converted to a drop in for whatever rifle you have. It would be a fun project. :thumbsup:

 

[bob308]

1-48 is the round ball twist for a .40 cal.

i did use a .38-40 bullet in a 1-48. but then that bullet is very short. had to make a false muzzle to load it.

 

[Loyalist Dave]

Thanks for the info folks; probably saved me some money. :grin:

Yes 1:48 is the current otc standard for round ball in that caliber, but the .40 has been shown to shoot very well with lesser twist rates too, such as 1:56..., but I digress.

OK so "I needs" a shorter bullet, IF.., it will work at all, unless I opt for custom molds.

So there is this short .38, but I think the design will make the bullet not seat consistantly..., maybe if it was swaged down to even up the diameter...??
.38 Colt Bullet

On the other hand this might be short enough, but the diameter is so small..., I'd have to patch the manure out of it to make it work...,
158 grain Wadcutter

Basically, I will probably get a .40 drop in barrel for my T/C just for fun. I was thinkin' if a conical was developed for it, it wouldn't be so anemic on deer. You have to admit that a 120-150+ grain conical would be better at beyond 50 yards than an 83 grain .380 all lead sphere. It would be nice to be able to use an OTC bullet mold or bullet, than to have a custom mold made. Oh well, should be interesting.

LD

 

[paulvallandigham]

Look at cast .40 caliber pistol bullets, and then buy a sizing die to size them Down in size to allow for the paper patching. There are lots of different designs, including bullets made for the old .38-40 revolver cartridge. Bullets in the 160-185 gr. range should be capable of being adapted to your needs.

I don't know how small a diameter you need to size down to, but with .457 caliber guns, sizing the bullets to .450" allows a couple of wraps around the bullet with onion skin paper. Most shooters who PP bullets run the completed and dried PP bullets back through a(second) caliber sizing die, to make sure that the PP bullet will fit down their bores without tearing the paper.

Remember that you have to have a good gas seal to keep hot gases from traveling up the grooves. If your groove depth is large, you may need to use a felt base( OP) wad or a filler or corn meal to fill those grooves and seal the gases behind the paper patching, to get good accuracy. :thumbsup: