boom stick -

Using a .429" bullet in sort of a long 444 Marlin has been done. The main shortcoming to the Marlin round is that a short magazine and action have restricted it to very stubby bullets. Frank de Haas made a lap die and increased the throat of a 444 Marlin single shot rifle. Then he worked up loads with various bullets, including swagged 300 and 400 grain Barnes 45-70 bullets and 385 grain cast lead bullets. To make it work properly he had his barrel made with a 1-16" twist Douglas barrel. He was getting 1850 fps with 300 grain bullet and 1500 fps with the 400 grain.

When you consider the 444 Marlin case is essentially a rimmed, straight walled .30-06 case it follows that you should look at .40 caliber -06 based cartridges . They are easy conversions for bolt action rifles and generate respectable velocities with heavy bullets. The .400 Brown-Whelen will shoot .411 diameter 300 grain bullets at more than 2400 fps and 400 grain bullets at over 2100 fps. The .411 Hawk, with very slightly more capacity, is another example.

Unfortunately, the greatest obstacle to creating and feeding a big .429 caliber wildcat is the absence of suitable bullets. If you want a full length H&H cartridge then I suggest you look at the 400 H&H. I have a mauser rebarrelled to 400 H&H. The 400 H&H is a really a good design and a great shooter.


The .30-06 and .411 Hawk

quote:

Originally posted by Grenadier:


Unfortunately, the greatest obstacle to creating and feeding a big .429 caliber wildcat is the absence of suitable bullets.

I was under the impression it was in fact the availability of suitable bullets for his wants

The way I read his stuff was this was to be a "fucking around rifle" but if some genuine big game opportunity arose then he could get some sort of big game bullet.

You are correct about his comments. "The pistol and 444 bullets are one of the main reasons to go 440." I missed that.

Using short pistol bullets at magnum velocities might bring the proper twist into question. In the article that de Hass wrote he was using one single shot rifle with a 1-38" twist and another with a 1-16" twist. The slow twist rifle did great with the pistol bullets but didn't stabilize the heavyweights. The fast twist barrel did best with the heavy bullets. This was in 444 Marlin caliber. The difference/problem would surely be greater in a .429" magnum.

The 1 in 10 worked well with 400 and 500 grains in 470. I was thinking a 12 twist might be ideal.

1 in 12 for what bullets at what velocity?

Using the KWK Calculator for Barrel Twist Rate, the ideal twist for:

- 240 gr Hornady HP XTP at 2500 fps is 1-42", at 2700 fps 1-43"
- 260 gr Hornady FTX® (444 Marlin) at 2500 fps is 1-31", at 2700 fps 1-32"
- 300 gr Barnes Buster at 2500 fps is 1-37"
- 410 gr Woodleigh .435" (need to swag to .430") RN SN at 2300 fps is 1-26", 2150 fps 1-25"

It is easy to see why de Haas got good results with pistol bullets in his 1-38" barrel.

Twist rates are really too fast in over 30 calibre. Remember that a 1 in 10 in 243 is much slower than 1 in 10 in 30 calibres. Twist would be best expressed as calibres. In fact I think that is done with artillery and naval guns.

Could you imagine a 16 inch gun with a 1 in 10 inch twist rate

Several years ago on a switch barrel bench style gun I did extensive testing with 338 Win, 358 STA and 375 H&H. The 338 had the standard 10 twist and the H&H a 12. The 358 STA had a 1 in 14. All match grade barrels that were number 5, about .72" diameter at muzzle.

As to best accuracy all three were much the same with their best load. However the, the 358 STA was easily the best when it cam to being very accurate with a wide range of loads.

While I have not done enough to have a definite conclusion I believe a rifle with a slower twist will show less wind drift.

Rifles will slower twists also seem more likely to put different loads closer to same point of impact and also more likely to put first shot from cold clean barrel in the general group and same for first shot from a barrel with cold hard fouling.

Yes, stabilisation is a function of rpms of the bullet,
and that depends on twist and velocity,

In the case of this wildcat, a lengthened 444 so to speak
I'd shoot easy to get, 250-350 gr, alloy lead, minie
bullets, at 2600 or more, and use slower twist barrels.
1 to 24 fine if you did use solid base and 1 to 38 with minies
At that speed they have the rpms needed to stabilise perfectly.
And solid base plated bullets too at 1 to 24 .

That gets us bullets the cheapest, cheaper barrels,and
slower twist get speed at less pressures, and over 2600 the barrels
won't lead up with alloy slugs. And alloy or good plated will penetrate
better than regular jacketed if that what you want.

And a case made from 45-120 brass will get that speed at pressures
that NEF break actions will handle easy, another money and time saver. Ed

After some thought I think a long and short would be interesting. 2.5" and 2.85". The 375 HH at the bottom of the neck is 2.5". You could cut off the neck and expand the shoulder part or form from 458 Win etcetera. The shortie could be good for pistol bullets at ludicrous speed, 444 bullets @2400-2500 or DG rifle bullets around 400@2150. That would cover many needs.

quote:

Originally posted by boom stick:
Any thoughts on .430" for big bore cartridges for carts more powerful than a 444?
A "440 Magnum" based on a 375 HH case?

I know someone here in Alberta that built such a rifle on a P-14: a .375 necked up to .429". I believe he was using Hawk bullets in the 400gr range.

Wow! Interesting... Do you know the length or any modification from the original 375HH case?
If you could get ahold of a pic that would be stellar.
Thanks!

quote:

Originally posted by kayaker:

quote:

Originally posted by boom stick:
Any thoughts on .430" for big bore cartridges for carts more powerful than a 444?
A "440 Magnum" based on a 375 HH case?

I know someone here in Alberta that built such a rifle on a P-14: a .375 necked up to .429". I believe he was using Hawk bullets in the 400gr range.

I am not sure if he is active on AR but here is what he emailed me:

"The rifle was a p-14 that was heavily modified to a sporter. We used a piloted 7 STW reamer to cut the chamber. Brass was 416 rem brass that was 'necked up' in a 416 rem die with a modified expander ball to get the 0.429 neck. I built a sliding seater unit (Hornady dies) that would fit the bullets and crimp.

Load data was:

78-84 gr H4895 300 gr Horn XTP

76 gr H4895 400 gr Hawk

Reformed 416 rem brass

WLR primer

Shot two mule deer does with the gun. Recovered one Hawk bullet that came apart and one that perfectly mushroomed."

Photo is 400gr Hawk / 300gr XTP / .30-06

Thanks for posting!
I see there is a shoulder to this cart so a tad different than what I had in mind but good to see that something similar has been done. I think the .430" diameter could make for a fine DG bullet diameter.