I've been shooting a MK II Martini Henry quite a bit lately, using fire formed Bertram cases. Having no dies, I don't size these at all. I prime with a small arbor press and seat a Lee 459-500 paper patched bullet over a weighed charge of SR 4759. 100 yard groups at a TQ4 are about 6 inches. As I finger seat this bullet to the 1st grease groove I've noticed a great deal of difference in the neck tension. Some bullets must be carefully seated to avoid tearing the paper while others will fall in if I'm not careful. My Questions: 1. Will neck sizing result in more uniform pressure and (hopefully) a smaller group size? 2. I've heard that a .480 Ruger sizing die can be used to neck size 450/577 cases. Does anybody have any experience with this method?
450/577 Martini Henry
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- Last Post 20 January 2015
I have some Bertram brass for my 43 Spanish RB. Neck wall thickness varies GREATLY and I get better groups sizing cases and then uniformly expanding with an “M” die. FWIW, Ric
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Hi Ric: Of course what you're saying makes perfect sense. If the cases are all fire formed in the same chamber and the bullets are all the same diameter after patching then variation in case neck thickness is the answer. This suggests a third possibility; using the same case. New question: If I'm competing in a military big bore or antique military postal match and I'm at the bench, finger seating the bullet before loading, am I within the rules?
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Hi Ric: Of course what you're saying makes perfect sense. If the cases are all fire formed in the same chamber and the bullets are all the same diameter after patching then variation in case neck thickness is the answer. This suggests a third possibility; using the same case. New question: If I'm competing in a military big bore or antique military postal match and I'm at the bench, finger seating the bullet before loading, am I within the rules?
I looked at the Military rules and there is nothing I can find that would cause you a problem.
Section 4 AMMUNITION REQUIREMENTS
4.1 Cast Bullet - A projectile made of lead or lead alloy which has received its basic form by being cast of molten metal in a mold rather than being formed in a die. A gas check having a sidewall height of no more than 0.10” may be attached to the base. Enlarging or reducing a cast bullet by bumping or swaging is permitted.
4.2 Cast Bullet Cartridge - An assembled round consisting of a primed center-fire cartridge case, a propellant charge, and a bullet meeting the requirements of 4.1.
To get the full Military rules go to the main CBA website (click on Home on the forum menu) and select Military Rules it's a pdf file so you will be able to save it. You might want to either neck turn and neck size or select the closest cases to shoot unsized.
I load at the bench at every match (gives me a chance to tweak the load as needed).
Hope this helps, Mike CBA Webmaster
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Thurman,
Mike has the right reference. The only issue is the time required; 10 minutes for five shots and 15 minutes for ten shots. Big bores are less wind sensitive than the little .30's, so you should be able to do well reloading each round.
Ric
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john A tells me to question everything ... so ;:
i question that a moderate .. or high moderate neck wall thickness variation would be significantly depraving of accuracy at the military issue level... assuming groups of 2 to 4 moa. AND that your load is achieving good ignition for all cases.
one reason being that unless there is an extreme crimp, the case neck has already let go of the bullet before the bullet moves much. the bullet is just left floating in mid-air ... EEK! ... that is one reason it is so important to have the bullet supported well by the chamber and throat before the big boom.
i like the way onondaga gary puts it ::: use as fat a bullet as you can chamber ...
just ramblin ken
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What I discovered, Ken, was that the lot of Bertram brass that I had was 0.015” thicker on one side of some case necks. If the bullet is laying crooked and cockeyed, it never straightens out after the big bang in the butt. It is not neck tension, but how it presents the bullet to the bore. Not only as large as possible, but as long as possible also. Ric
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Holy Frijoles! After reading Ric's last post I got out a pin mic and checked the wall thickness of the 20 pieces of Bertram that I have. Total variation was .0125 to .016 with a maximum difference in an individual case of .003. I do have 5 pieces that are .0145-.0150, so I reckon for the short term I'd better just work with them. Ken's post does present a conundrum. If the bullet is too small to be properly supported I can't increase the bullet size without dies to increase the case diameter. I've held off on buying the dies because they're quite expensive (larger size), but I can borrow a big press and that may be the only long term solution. Thanks to all for the input.
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hi ric:: 10-4 on offcenter necks. i would turn them and get a yet fatter bullet ... i guess it's the challenge of shooting production rifles.
i spent years in my job shop trying to convert badder shipped in parts into gooder shipped out parts. i figgered out it's easier and cheaper to make them right in the first place.
i think someone made 450 brass out of some? gauge brass shotshell cases.
ken
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No Ken, I had some of that junk. It's stamped CBC and was sold by some “old western” kinda guy. This is stamped 577-450 BB with a genuine Kangaroo on it. $100+ just doesn't buy what it used to! At any rate, thanks again for the input.
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Back when I used to load for guys with the obsolete rounds including regulating double rifles it seemed Bertram brass all had very uneven neck walls. I also got in the habit of annealing it right off as it seemed to split quickly if I didn't.
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I made .577 Snyder cases from brass 24 ga. shot shells. They came from Cabela's. The 45-577 got it's man hence I believe. My cases take a regular large primer. They are a balloon head case and are hard as heck. I need to anneal every sizing.
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"What I discovered, Ken, was that the lot of Bertram brass that I had was 0.015” thicker on one side of some case necks. If the bullet is laying crooked and cockeyed, it never straightens out after the big bang in the butt. It is not neck tension, but how it presents the bullet to the bore. Not only as large as possible, but as long as possible also.” Ric What Ric writes is true. That is why I “skim” turn the necks on all my cases right out of the gate including commercial. Especially when making .308s from “06” mil. issue. When loaded with a true cast bullet and checked on a concentricity gauge, the runout will be minimal. The results will also be seen on the target.
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If you really want to find out if neck tension is one or your problems why not shoot several groups with one case alternating with several with mine run cases. This will give you a better answer for YOUR gun, sights, bullet, and bench technique that all the theory you can muster.
Same way with the truly horrible neck wall thickness variation from one side to the other. Groups with one good case (if you can find one) against groups from the mine run cases.
Shooting one case in competition eliminates some variations but that's the right answer to the wrong question. The first question should be are the variations hurting anything. I wouldn't take the extra trouble to shoot one case only in competition until I proved to myself that shooting one case is better than using 'um all.
Actual experimentation with the particular gear, shooter, sights, bullet, etc. will beat theory and “what's logical” every time.
I think cast bullet shooting, and many other areas, have too little of the former and too much of the latter. But then you knew that.
John
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Just a heads up- Lee Precision offers dies for 577-450 Martini Henry and 577 Snyder for $125. I brought a set of their 577-450 dies several years ago and have been happy with them.
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Thanks rjmeyer, I knew that Lee was making a (relatively) inexpensive die set. It's good to know that they do the job.
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I wrote an article about shooting the 577-450 Martini Henry for the Fouling Shot about 8 or 9 years ago. I have been shooting my MkII and MkIV using reformed CBC 24 gauge all-brass shot shells and various loads both smokeless and real Black powder. I have the Lee dies but rarely use them. These size my brass way too much necessitating both annealing and a larger expanding button to seat the proper size bullet. The M/H barrels have a really long, tapered throat starting as the case mouth. The MkI, MkII, and MkIII have groove diameters of about .462 to .466, The MkIV often have groove diameters of .468-.472. Almost any of them will chamber with a bullet significantly larger than groove diameter. Using my CBC brass, I am able to “thumb-seat” LLA coated bullets of .482” in diameter (both grease-groove and paper-patched)in fired, unsized cases and have them chamber easily. Accuracy is significantly better with the larger bullets despite practically no neck tension. One thing I have found shooting these rifles is that some of them do not have breech blocks that lock perpendicular to the chamber necessitating indexing of brass to avoid having to full-length sizing.
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Thank you curator: A wealth of information in one paragraph. My MKII slugs right at .464, and while I haven't taken a chamber cast yet I have suspected a long, large throat. Looks like it's time to dig out the Cerrosafe and then (probably) start looking for a mold that casts a really big bullet.
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Try the Lee .475-400RF bullet mould. Mine casts at .482 with “mostly” pure lead and 2% tin. While the slug does not have enough lube groove space for a good black powder bullet, it works great with smokeless reduced loads. (I use both SR4759 and IMR4198)The lee mould is inexpensive and easy to use. Pushed to about 1150-1200fps it is quite accurate to 100 yards lubed only with two coatings of LLA.
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Just a little heads up on the Lee dies. They are too big to go in the 7/8"hole of a normal press.
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Incidentally, I went to the range last week and shot 20 rounds thru a single case (wall thickness .0145/.0150) and while the groups did shrink I still don't feel that the load is competitive. Nice to know about the .475-400 Lee bullet. I was going to use the Greenhill formula because of concerns of the bullet being too short, but 100 yard accuracy in a frugal package is right up my alley. I believe I'll put off buying the dies until after I experiment some more. I can borrow a bigger press but if a chamber cast and a fat bullet will solve my problems...
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I'm happy with my Mk3 using Bertram brass
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