I don't know if it can be done but I need some QL help!

[taylorce1]

Thinking of a wildcat cartridge, basically a .338-375 Win. I've got a nice little M788 Rem bolt action rifle in .30-30, and just wondering what would happen if you necked down a .375 Win case to hold a .338 bullet since I could run spitzers in this action? I figure if I can push a 200 grain bullet around 2400 fps like the .375 Win can it might make a cool cartridge.

The closest thing I can find is the .338 Woodswalker which had data of a 200 grain NBT at 2000 fps out of a 10" contender pistol barrel. I doubt I'd ever build this rifle as I like my little bolt action .30-30 too much. However if the right deal came along on another, but far more abused M788 came along I might entertain the thought.

So here is what I'm thinking.

2.450 COAL
22" barrel 1:10 twist
47 grains water capacity 34-35 grains with bullet seated
200 grain Hornady SP (think the AB might be too long with my COAL)
50,000 CUP max

So is 2400 fps folly or not?

 

[FOTIS]

Look at the 338 JDJ 444 marlin brass necked to 338

http://www.handgunhunt.com/tech/t25/index.html


would rock from a rifle! Even with a 16" tube!

 

[FOTIS]

BTW super strong brass!

 

[taylorce1]

I was talking about my 788 .30-30 the other day with Kevin Weaver who told me he has built a few .375 Wins on the M788. I know the JDJ's work I've ran a few in my Encore, and the brass is better. However, I don't think it will work in the M788 without serious modification that is why the use of the .375 Win brass which is much tougher than the .30-30.

 

[taylorce1]

Plus I'm very limited on magazine lenght with the M788.

 

[SJB358]

Yeah, I would think the 338/444 would be a cool cartridge.. Even cooler would be the 35/444.. Seems like more bullets in the 35 cal class for a cartridge like that..

I tried to look up something in QL to run numbers, but I don't have anything close. I would imagine if Mike see's it, he may be able to come up with something cool though.

 

[taylorce1]

I've ran the .375 JDJ out of a 26" Encore and got 2400 fps with the 260 grain AccuBond, and 2600 with the Speer 235 grain bullet. 270 grain Speers gave the best accuracy but finding the jackets without cores laying on top of the dirt back stop didn't leave me with a warm and fuzzy feeling. Anyway I never killed anything with the barrel before I traded it off for something else.

 

[taylorce1]

225 grain AccuBond pulled from an Alaskan Black bear in 2007 out of a 14" .358 JDJ Contender Pistol.

viewtopic.php?f=5&t=4546&hilit=.358+alaska+bears

 

[FOTIS]

That looks great!

 

[SJB358]

Very cool. I'd love to have a 358 JDJ.. It would kinda round out my 35 cal's..

 

[taylorce1]

Got a rough idea of the cartridge from a guy on AR!

 

[Oldtrader3]

The Model 788 is a rear lug action with only (9) small lugs in (3) sets of (3), kind of like a mini Mark V Weatherby rifle, only with rear lugs. The limits of this design and trying to build it into a larger case footprint would be impractical for the increased thrust created by the Pi x r2 with a larger bolt radius than the original .30-30 brass head diameter. Column bending shear stress would be another issue for changing the 788 design to a bigger column diameter with more column compression on smaller length lugs. You will remove compression area by making the lugs shorter when you increase the column diameter for the bigger case base diameter.

Getting all of the lugs and newly machined bolt face blueprinted in a reverse shear lug design like the 788, would be difficult to machine and attain needed tolerances in a used gun. I am not sure that this project would be worth the trouble as you would still have a 788 action when you finished which you had not added any value to.

 

[taylorce1]

The Model 788 is a rear lug action with only (9) small lugs in (3) sets of (3), kind of like a mini Mark V Weatherby rifle, only with rear lugs. The limits of this design and trying to build it into a larger case footprint would be impractical for the increased thrust created by the Pi x r2 with a larger bolt radius than the original .30-30 brass head diameter. Column bending shear stress would be another issue for changing the 788 design to a bigger column diameter with more column compression on smaller length lugs. You will remove compression area by making the lugs shorter when you increase the column diameter for the bigger case base diameter.

Getting all of the lugs and newly machined bolt face blueprinted in a reverse shear lug design like the 788, would be difficult to machine and attain needed tolerances in a used gun. I am not sure that this project would be worth the trouble as you would still have a 788 action when you finished which you had not added any value to.

?????

The .375 case is basically the same as the .30-30, I'm not really increasing anything other than the bullet diameter.

 

[Oldtrader3]

Your case drawing wasn't up when I started reading this, anyhow, it still holds because the thrust of the bullet and gasses will be based on a .338 bullet, not a .308 so bolt thrust forces will still be Pi r2 (.338) +Gas ejecta and bullet weight (going Mach 2+). however, not .308, even if the case head diameter stays the same, the thrust will increase.

 

[taylorce1]

I understand there will be some extra bolt thrust, however I was confused by all the extra work you had stated that needed to be done to get the cartridge to work.

 

[RiverRider]

Charlie, aren't the only two factors in case head thrust the chamber pressure and the case head area?

 

[taylorce1]

Finished up with the QD and QL! I was hoping it would be a little faster, but 2300 fps is no slouch out of a small case with a 200 grain bullet.










Plug the numbers into JBM and BAM!

 

[SJB358]

The only thing I could think of would be 60K on a 375 Winchester case.. Might be a little stiff..

 

[taylorce1]

It's a little hot and I'd definitely work up to it when compared to a max load in a .375 Win.

.375 Win
200 GR. SIE JFP Hodgdon H4198 .375" 2.530" 35.0 2288 36,900 CUP 38.0C 2480 50,600 CUP

PSI TO CUP

(PSI + 17902)/1.516

(61891 + 17902)/1.516 = 51,116.59 CUP

 

[SJB358]

Gotcha. Makes sense now. Your right though. That'd be a hammer!