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Thread: 577/450 Martini Henry Case Problem

  1. #1
    Boolit Master mtnman31's Avatar
    Join Date
    May 2007
    Knoxville, TN until I get back to Montana.

    577/450 Martini Henry Case Problem

    I fired my MkIV Martini-Henry for the first time today. The rifle is a IMA rifle with a pristine barrel and chamber. First shot went off and clocked 1200fps. Second shot clocked 1010fps and the case separated. I am pretty sure I know what happened and need a few of you to chime in and tell me what I did wrong then roast me for doing something dumb.

    Top round is loaded cartridge.
    Middle is first round fired.
    Bottom is second shot fired. As you can see, the neck and a good portion of the shoulder ended up in the barrel. The brass is a nice representation of the rifling

    The load was 85gr of FFg, and 20 gr of Cream of Wheat under the RCBS 468-485 FN, all stuffed into converted MagTech 24ga shot shells. Let me know what you think.

    I'd like to be able to throw out a disclaimer or excuse as to why I screwed this load up, but nothing creative comes to mind.

    So, what I think happened is that the COW was below the shoulder and when I fired, the COW became a plug that ripped the case apart. Fortunately, since this was the first time loading for this, I only loaded five rounds. The converted shot shells have fairly thin walls and even 85grains of FFg leaves a ton of space in the brass.
    COW was not the answer and I know better but I guess I just didn't give my load a sanity check.

    Maybe one of these days when I have a few hundred extra dollars lying around I'll get a box of 20 Bertram cases. If someone has some 577/450 Bertram cases, I could trade a box of new .43 Spanish Bertram cases...

  2. #2
    Boolit Master
    elk hunter's Avatar
    Join Date
    Jan 2009
    Central Oregon
    Never had that happen, but I don't load 577-450.

    Your explanation sounds possible. I use COW to straighten bottle-neck cases by fire forming and have had some split when I didn't anneal them first, but never had one come completely apart.

  3. #3
    In Remembrance
    montana_charlie's Avatar
    Join Date
    Feb 2006
    West of Great Falls, Montana
    martinibelgian shoots that cartridge in competition around Europe.

    You may want to search out and read some of his posts (or PM the man), but I'm pretty sure he routinely fires black powder charges that do not totally fill the case ... and I am certain he uses no fillers.

    Retired...TWICE. Now just raisin' cows and livin' on borrowed time.

  4. #4
    I think Murfys law played a big part in this.I know COW is not the best filler for this cartridge(kapock is recomendes to be very good for botle neck cartridges,I use brecfast oats),but I have seen many rounds fire formed with the exact same load as you used with no trouble,have you fired the other 4 yet.It may pay to measure were the sholder starts in a fire formed case and adjust your forming die to suit,at least this would give more suport on the first fireing

  5. #5
    Boolit Master
    Join Date
    Mar 2010
    Hello, mtnman31. Your right on about that cow becoming plug..under presssure it becomes nearly solid..last year, I was shooting a .25-25 Stevens....this is a long straight case. I was using slightly reduced loads of Swiss 3FG. To fill extra space I used cow..had case seperation..the others that didn't break were stretched 1/16"! I tried Puff-Lon, with good results..but it's messy (don't sneeze!)

  6. #6
    Boolit Master

    Join Date
    Nov 2007
    Mtn West
    I think you answered your own question. It is well known that COW and similar type fillers will do as you described in BP rounds that have the bottleneck like the 577/450. I use various solid wads (not low density wads) in all manner of BP carts including those with bottlenecks. I use cork, felt and hard fiber. BUT, I do not use material like COW in bottlenecks and for certain do not put any of the dense BP type wads below the neck. COW does act like a hard, high density wad when loaded and compressed by igniting powder. The Martini shooter mentioned earlier does shoot BP with airspace I think and this very subject about this particular cartridge has come up many times on this forum. You can take the advice of using airspace to reduce BP loads if you like. I will not do it. Just my opinion.

  7. #7
    Boolit Mold plourbag's Avatar
    Join Date
    Jul 2011
    Laurieton, NSW, Australia.
    mtnman, I suggest you post your question on it is an Aussie site and a lot of us shoot Martini 577/450s. A couple of my mates use that site and may be able to help.

  8. #8
    Boolit Master enfield's Avatar
    Join Date
    Feb 2007
    Nova Scotia


    yup I think you could be right. I assume the cases have been well annealed. mine get annealed about 5 times through the reforming process. I have mostly used the 50/50 COW & BP mix to fill up the last 20+ grains into the neck but I did try loading a column of BP up the center of the case with COW around the wall of the case ( used a straw to make the BP center column ) it was failure as the COW still formed a solid mass but it came out the barrel in chunks & didn't brake anything. I have also stuffed the fluffy hair from my dog on top of the main charge of BP with no Ill affects. ( well maybe it smells a bit )

    hey, watch where ya point that thing!

  9. #9
    Boolit Master
    Join Date
    May 2012
    Outside Rolla, Missouri
    I worked with this cartridge and rifle 15 or so years ago in working up a load for a friend. I used corn meal for filler....which should act about like COW. I did not experience your problem but I do believe you're right about it turning into an "almost solid". If doing so today I would not use either one. For loose fillers these days I used Grex or packing foam. I particularly like the packing foam but am becoming a bit trepiditious about its use.

    The rifle isn't a double but one might benefit from Grahme Wrights book, "Shooting the British Double Rifle". He and his friends in Oz have done lots of work on shooting the big BP cases and have pressure tested many loads at both Kynoch and Birmingham Proof House.

    Seems to me plourbag and montana charlie have the best suggestion, there is no substitue for experience.
    "In general, the art of government is to take as much money as possible from one class of citizens and give it to another class of citizens" Voltaire'

    The common virtue of capitalism is the sharing of equal opportunity. The common vice of socialism is the equal sharing of misery

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  10. #10
    I do indeed shoot 577-450 with airspace. Why? 2 reasons:
    - To load a 577-450 case without airspace would require 100+ grains op powder - that HURTS, certainly in the typical military martini.
    - W. W. Greener in his book "The gun and its development" specifically warns against the use of a full case of too fina a powder granulation, and recommends as solution to use partially-loaded cases in order to avoid excessive pressures and bursting barrels.

    I do believe that W.W. Greener probably forgot more about BP than we know (after all, several generations of Greeners preceded him) - and if he says it's OK, I do believe him. Up to now, I have shot quite a lot of rounds loaded as such, without any ill effects. Works very well, is pretty accurate. Is it ideal? Probably not as regards accuracy, but good enough. Is it dangerous? If done correctly, IMO no. If after 1000+ rounds in several original rifles, nothing has happened, I don't believe it ever will. I am of the opinion that the use of the improper filler (like CoW below the BN) is much more dangerous than an airspace between powder and bullet (or to put it differently, loose powder under a bullet). You can read a lot of urban myths on the 'net, and IMO this is one of them. Fillers like CoW might work well in straight cases, but in BN cases when loaded below the neck, it's an accident waiting to happen. It would also be pretty hard on the barrel, not to mention the excessive pressures generated by that plug...
    Luckily, a Martini is pretty safe as to escaping powder gas, but with other actions...

  11. #11
    Boolit Master
    Join Date
    May 2012
    Outside Rolla, Missouri
    martini, I'll have to agree with you regarding Greener. I have his book, "The Gun and its Development", (I think that's right). I remember the first time I held that huge case in my hand and thought, "surely they didn't load this thing thing full?". I didn't and you're right, it would hurt! Especially in a Martini!!

    As I'm ever curious, may I ask what your load is for your 577-450? Frank Barnes in the 7th edition of his book shows two loads, 80 grs. of black and 38 grs. of IMR 4198. The black load under a 500 gr. bullet and the smokeless under a 400 gr. bullet.
    "In general, the art of government is to take as much money as possible from one class of citizens and give it to another class of citizens" Voltaire'

    The common virtue of capitalism is the sharing of equal opportunity. The common vice of socialism is the equal sharing of misery

    NRA Benefactor 2008

  12. #12
    Boolit Buddy
    Join Date
    May 2010
    Eastern Norway
    I have had good luck using COW in the 577-450. BUT I mix it with BP. Actually 2/3 BP and 1/3 COW, 85 grs Swiss no 4 under it. I think 50-50 would be just as good. Almost any kind of filler bellow the neck would hurt your brass. A friend of mine use powder all the way up to the neck and then a big fat grease wad. Works well too.

    I have heard that you can get lathe made brass that are straight on the inside. I don`t know who the manufacturer are though.

  13. #13

    I mostly use the LoC load of 85grs of Swiss Fg (no.5), sometimes going upt to 90, usually behind a 530gr .468 bullet. Shoots pretty well in all of my 577-450's (about 5 - I think).
    Depending on the weather, I use a grease cookie/lubed felt wad or not, and the bullet might be either PP or GG (the PP of course always requires the grease cookie or lubed felt wad).
    The bullet was designed with a long shank, in order to take up as much room as possible, both in the case as outside - this also helps reduce case capacity.

    1 thing though - a PP bullet required a very good to excellent, smooth bore - otherwise you'll only get it to shoot well with wiping between shots.

    I use both modern drawn brass as well as converted CBC (Magtech), which indeed has the issue of even more case capacity.
    It being a BN case means it can efficiently use slower powders like Fg - which also have the added advantage of reducing felt recoil.

    All my shooting usually is prone, with sling, unsupported - a military martini wasn't designed to be shot benched.

  14. #14
    Join Date
    Jun 2007
    I have read about active filler on
    Filler made from 50-50 to 75-25 COW to BP ratio.
    The burning powder will eleminate the caking thing once and for all.

  15. #15
    That active filler - sorry, it doesn't work as advertised: The CoW will NOT burn in the barrel, and tends to separate out from the powder (even a card wad won't burn, it won't even have scorch marks). For me, it most certainly is not the solution some claim. Accuracy is done by eliminating variable, and fillers (mixed or not) are a variable added, sometimes very difficult to control. Usually, simpler is better IMO.

  16. #16
    Boolit Buddy

    drhall762's Avatar
    Join Date
    May 2011
    Ammon, NC
    I have a dimensioned diagram of the lathe turned 70 grain capacity cases. I have not made any yet but have made several based on the same idea for some 7.62 NATO special purpose ammo.

    In 100 years who of us will care?
    An armed society is a polite society.
    Just because they say you are paranoid does not mean they are not out to get you!

  17. #17
    The original Military 577-450 carbine load used cotton wool as a filler,I do nt like this as there is a snow storm every time you fire it,kapock is a natural filler that will not form a plug in the case and is cleaner.I have used rolled oats for over 20 years and have never had any trouble and have won quite a few matches using it as a filler,though I will be changing to kapock

  18. #18


    Herbert, Martinibelgen,
    I have heard of cotton and wool being used as a filler, mostly just to take up the space and keep the powder against the primer.
    Could dacron be used succesfully?
    I use it in a lot of smokeless loads and it works quite well.
    It is very similar to cotton.


  19. #19
    Boolit Master
    Join Date
    Mar 2005
    A number of BPCR shooters report that they have case neck shoot offs at the location of the cannelure ring.
    Some of these result in the case neck going down range with the bullet.
    I think that even compressed black powder can grab the case and pull the case mouth off. Surely COW can.
    I thought of a case design to deal with this in the very large capacity cases but I think the market is too small to mess with.

  20. #20
    Boolit Bub
    Join Date
    May 2008


    While i do not own a martini henry i have plans on how to load for it.i have a advantage, i own an old but still good Lathe. my father used to make Lathe turned cases from Naval rolled brass,but that's a big job.I throught i'd make some brass inserts,tapered to match the 24ga Brass Shells, and straight on the inside.Crimp them below the bottleneck and they would never go anywhere unless the cases split.i'd use a 7/16" drill, so the case would be no more eighty grains of fG or so when full.Also since it would be a straight case on the inside you could compress the powder if neccessary. I think this would work.When the cases break, i'd remove the insert and keep it for another case.

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Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check