5,000 fps?

joes

I have followed a post on wssm forum and a couple of guys are looking to to create a wildcat 204 wssm that should clock in at about 5,000 fps. with 32 gr. pill. Do you guys think the bullet will hold up and can it be controlled at that speed. Will the barrel hold up at that speed? your thoughts- (does sound like fun to play around with).

Tailgunner1954

With a slow enough twist rate, or a monometal bullet, the bullet should hold up until it reaches the target.
A lot of guys talk smack, but only a very few are willing to do the deed. Ever hear of the "22 Eargensplitten-loudenboomer"? It reached that kind of velocity, but the throat/barrel life was IIRC 5 rounds or so.
IIRC the gas expansion velocity is somewhere in the 5Kfps range, so there fighting a tough battle right there.
What barrel length are they working with, IE Expansion ratio. Divide the bore + case volume by the case volume, IIRC they'll need something over a 6:1 ratio inorder to have a prayer of making their goal.

Now, if they want to use a 338 or 375 bore and a sabot, they might have a better chance.

cce1302

I don't know, but I'd like a matching pair, consecutive serial numbers, built on remington action.

bgjohn

Y[?]
JM

joes

I can't see it, with a 223 wssm even the slightest load on the hotter side splits the necks on the cases almost every time. ( that is the brass cases not sure what the silver cases do).

dcloco

tailgunner has it right.

Need the case capacity to hold that much powder...to propel any bullet at that speed.

charliemeyer007

For ball park facts: I read that max velocity for burning gun powder is around 6200 fps. It uses about 20 percent of the available enery to spin the bullet. The 120mm Reinthol on an M1 Abrams throws fin stabilized dart at 5600 fps from a smooth bore. I wanted to make 7mm boattails sabots for a 458 mag. I'd be real happy with a 162 gr at 4400.

nononsense

joes,

"...and can it be controlled at that speed."

The control is a function of the twist, the straightness of the hole in the barrel and the perpendicularity of the crown. You have to have the best concentricity between the action, barrel and the chamber. Once it leaves the barrel, we're out of luck.

"Do you guys think the bullet will hold up..."

I worked on this a few years ago using the 22-250AI, the 22-243AI and a 30" barrel. Any of the cases with 53 - 56 grain capacity will work

Depends on which bullet you choose and the quality of the lands and grooves. In applications like this an alternative rifling form can be real handy. The Broughton 5C, or one of the very best polygonal designs (5R, Schneider, Lothar Walther, etc.) will do wonders for having the best characteristics which treat the bullet a little more gently on its trip down the barrel. These rifling designs also create less damage to the outside of the bullet which makes for a smoother trip down range.

I used custom monometallic bullets designed to overcome a portion of the friction as well as stand up to the linear and rotational velocities. They were NOT coated. I got these bullets, which weighed 35 grains, up to a little over 5,000 FPS consistently. Not by much but consistently. The real work is in the testing of powders and brass cases in order to balance out the pure velocity against safety and usable case life through reasonable, although high pressures. You can't get to these velocities without running on the edge of the maximum pressure range. There are some other tricks but you need to have some fun discovering some things for yourself or at least the other guys do.

The case shape of the .223 WSSM actually works against these attempts at hyper-velocity most especially with the smaller .20 caliber bullets. The powders that are suitable for the velocity race don't respond well when they clump in the outside radius of these bigger diameter cases. Try it, you'll see what I mean.

The other problem with the WSSM cases are the necks, they're too thick and they need to annealed so they don't crack. Your friends need to figure this out before they take on a project like this. It's a long learning curve without a bunch of preparation and testing.

There is some background on two cartridges used for this over on ReloadersNest.com, it's not mine but they are over 5,000 FPS.

Best.