Max charge weight for 425 gr "One Ounce Suppository"... Predictions?

[FrankenMauser]

Some time between now and the 5th of July, I'll finally be testing my 425 gr "FrankenBullet" for the first time (as mt_sourdough refers to it). It will be pressure-testing, only; but testing, none the less. I'm going to push it as hard as I can, to determine what the maximum load should be.

mt_sourdough, FlatTop, and a few other MO members have done a lot of the foot work in getting some solid starting loads worked out for super-heavyweight bullets in .444 Marlin (400+ gr), but I'm in a slightly different situation.

Where most .444 shooters are restricted to an OAL of roughly 2.550" (or shorter, if using wide meplats), I don't have any OAL limitations. My .444 is an H&R Handi-Rifle, and the 425 gr FrankenBullet (lovingly called the "One Ounce Suppository" by my brothers) is a bore-rider. This bullet was designed for a 3.240" OAL, with 0.500" (+GC) seated in the case. ...which gives me significantly more case capacity than anyone adhering to lever gun loading and feeding requirements. (Drawing at Accurate Molds site.) I believe it works out to almost 12 grains additional capacity, when working with H4198 and H4895-- when compared to similar weight bullets at 2.550".

So, I'm in (seemingly) uncharted territory, here. Which has me really stumped as to what I'll actually achieve with the initial testing, and had me wondering what some of the other .444 shooters might predict for a maximum charge weight.

Although case capacity and bullet weight put me solidly into .45-70 territory, I'll be starting a fair bit under that. I've been planning to work up from 30 grains of H4198, with a (likely compressed) target of 50 grains. However, I've been considering bumping that starting load to more like 35-36 grains, lately.
I could be a little more specific about charge weight for compression and actual capacity if I could find my dummy rounds. I have more notes with those rounds, but can't find them right now. The last time I was in the reloading room was in early March.

Working through all the super-heavyweight .444 data and 425-450 gr .45-70 data I could find, my hunch is that I'll start seeing primers complaining about pressure around 46 grains. But... I. Just. Don't. Know.

Predictions?
Questions/comments/concerns?



Photo below, all .44 caliber, left to right:
Lee 200 RF, 275 gr bonded bullet**, Lee 310 RF, 330 gr bonded bullet**, 437 gr FrankenBullet (Isotope alloy ~11 BHN), 425 gr FrankenBullet w/ GC (heat-treatable WW equivalent from pure lead and linotype, +2% tin, +2 ounces magnum shot)
**.40 S&W and 10mm Auto brass. See the sticky in the reloading forum, for more information.

[mt_sourdough]

FankenMauser, I dig this discourse. My guess is you won't reach 50gr of either powder mentioned. Maybe, 48.5 grains with H4198. I guess it depends on how compressed you go. You will be able to stuff 50gr with compressed loads, but I suspect serious red zone territory as far as pressure. This is just an semi-edumacated guess.
The amount of bullet in the case is about equal to what Flat Top is using in his Safari Grade, you may have slightly more case capacity depending on your final COL. At it's max, I suspect you'll be pushing the Franken Bullet between 2000 and 2100 fps, maybe a little more. I'd be interested in hearing how that will feel in your rifle, because you are running with Flat Top's type of numbers. His rifle deals with the recoil like water off a duck's back, in my opinion.
Another note, RL7 has the same fill rate as H4895. Flat Top is sold on RL7 for top velocities in his application.
I worked with H4895 for safety reasons. It would be hard to reach danger zone by under-loading or overloading with H4895. With H4895, I'd start around 36 or 37. One of the great things about working test loads over a large range, is you can find many sweet spots and based on your needs for specific loads, you can always fall back to lighter loads if wanted.
As far as creating dummy loads, your bullet gave me fits creating a dummy load. My original thought was the nose type would allow a longer COL. My first dummy load test was with 2.575" and it jammed in the throat/barrel and would not extract. I had to come in from the muzzle end with a cleaning rod to push it out. I repeated this process a few times. The reason why the FrankenBullet jammed and wouldn't extract is because your bore ride fits tight in my barrel. I'd have to find my dummy round to determine what my final COL was but if memory serves, it was somewhere between 2.525" and 2.545".
It is loading through the loading gate with long bulge in the case is why the COL must be shorter with the super heavyweights in Marlin Rifles. Of course you do not have that issue. Flat Top's Safari Grade has had a lot of modification in the loading gate area. I'll be following this thread with much anticipation.

[FrankenMauser]

My bullet departs from most modern designs and returns to old-school (competition) methods with a cylindrical nose, rather than the mild taper generally found on today's versions.

Because I spec'd the design exactly to my bore, there was the slight chance of machining tolerances causing problems. And, that did occur with the mold I currently have. There is a very slight over-size where the cylindrical portion transitions to the ogive, of 0.0003". In the photo above, you can see where I bumped it down in a .427" sizing die (with spring-back to ~0.4282", if I remember right); because I, too, had some chambering issues. With softer alloys, the shrinkage is enough to negate this oversize, but it does cause problems in my various WW-based alloys.

I hadn't realized that FlatTop's case capacity was so similar to my own. I'll take another look at some of his data.

[mt_sourdough]

FrankenMauser, I too, didn't realize how close the two were until I started replying to your post this morning. The FrankenMauser will have slightly more case capacity than the 410 gr Safari Grade and has about .10" to .15" more case capacity than does the 445gr Safari Grade bullet. Understand that Flat Top's numbers are actually produced from fairly conservative loads. He can push his bullets harder if he wanted to, but he accomplished what he set out to do and decided not to go pushing the envelope. I am not really sure how your rifle will compare as far as pressures are concerned. Your action is stronger, but I wonder if the case strength becomes the limiting factor in your situation. I do not know.

[dpe.ahoy]

I have one of the H&R 444's as well, but haven't run any heavy weights in it. So far, mine has been a very good shooter with the 2.5 MOA red dot sight I have on it. Have to try it out with a scope one of these days and see what she will really do. DP

[FrankenMauser]

FrankenMauser, I too, didn't realize how close the two were until I started replying to your post this morning. The FrankenMauser will have slightly more case capacity than the 410 gr Safari Grade and has about .10" to .15" more case capacity than does the 445gr Safari Grade bullet. Understand that Flat Top's numbers are actually produced from fairly conservative loads. He can push his bullets harder if he wanted to, but he accomplished what he set out to do and decided not to go pushing the envelope. I am not really sure how your rifle will compare as far as pressures are concerned. Your action is stronger, but I wonder if the case strength becomes the limiting factor in your situation. I do not know.

I only run standard Large Rifle primers in the .444. In this case, it will let me read the primer before the case is anywhere close to failing in any way. Plus, in "uncharted territory" situations like this, I use the micrometer-on-the-case-head method for making sure the case head doesn't expand before a primer shows issues.
(I was in a similar situation, working up loads with W780 Supreme, in .220 Swift and a couple other cartridges, when the powder first hit shelves. It was... time consuming, to say the least; and most of the cartridges still don't have data for that powder. But, I ended up with some incredible loads that were well worth it; and I never would have pushed as far as I did to find a max load, without knowing the case head was still safe.)


My original intent with the bore rider was to hit 2,000 fps. After some serious internal debate, I decided to back that off to 1,800 fps. But... I won't stop until I get pressure signs, so I know how far to back down from max for a safe working load range. If that means I get to see 2,000 fps, I'll be quite happy. If that means I have to stop (or consider other powders) at 1,600 fps, so be it. It's all a big experiment. Data is data, even in "failure".


I know there was more I wanted to mention, but I'm having some connection issues here. I'll post tomorrow, if I remember what it was...

[mt_sourdough]

With my 450gr Hamfist, I hit a comfortable 1630 fps. The Hamfist fit the chamber poorly. With a better fitted bullet, I am sure id pick the velocity a bit more. That was with 36gr of H4895.
hamfistfrankenbullet004.jpg
Hamfist next to Frankenbullet.

[mt_sourdough]

FrankenbulletSafarigradebullets001.jpg
Here is the Frankenbullet with the Safari Grade bullets. Flat top pushes all those Safari Grade bullet well over 2000 fps conservatively.

[Canuck Bob]

Prediction, a bonafide Cape Buffalo rifle. As always these super heavyweight discussions teach us a lot about our rifles. With your case capacity you can lean toward slower powders which I understand may benefit such a big bore-ride bullet.

I have a Handi in 22 Hornet, talk about the other end of the power spectrum.

[FrankenMauser]

Thanks again, mt_sourdough, those picks definitely add a different perspective.

Canuck Bob, I'm sure your Handi-Rifle lets you get a bit more out of the Hornet, as well. It's such a shame to have so many Hornets out there with severe OAL limitations, due to magazine or action dimensions.


Apparently, I don't have enough of the FrankenBullets lubed and ready for all of my testing. Time to crank up the double boiler....