MH .577-450 Boolit

[Ed in North Texas]

I got my Martini-Henry Mark IV .577-450, though I'm not home yet to slug the bore, cast boolits, or start reloading the .577-450 cases. OTOH, we know the bores on these rifles run significantly larger than the earlier rifles, generally .468 or so. I have the Lee .470-400 grain mould on the way, and yesterday I picked up a Mountain Moulds .477-475 grain .480 Ruger mould from another member of the board. RCBS has a .474 diameter die for the Lyman-RCBS lubrisizers. Any opinions on how sizing the .477 down to .474 might do in the Mark IV M-H? Who knows, someone on the board may have already gone the .480 Ruger route.

[The Double D]

THe Martoini likes heavier bullets, 480 and heavier.

Try the .470-400 and see. I think the .477 will be to w big and sizing the down might not work

You want to slug the throat of these rifles and fit the bullet the bullet to that. The throat in the Martini extends 8 inches from the breech.

[curator]

I shoot the Lee .475-400 bullet in my Martini MkII with good results. Having made a throat cast, I discovered that the as cast diameter of .478 would not be a porblem. I cast them of 1 in 40 tin-lead alloy and double lube with Lee liquid alox. They are a thumb fit in my fired brass (converted 24 gage brass shotshells) eliminating case sizing. I do index them as the breech block on my rifle is not perpendicular to the chamber. I use Ross Siefied's smokless-for-cordite loads with dacron filler. These have about half the recoil of the 480 grain slug and 85 grains of black powder with better accuracy (and no bruises)

[Boz330]

I have had really good luck with a 385gr slug that was made for a trapdoor at .462. I use BP so it must slug up pretty well. This is in a MKII though with a .468 throat. I have a proper mold for it now but the old one has worked so well that I haven't fooled with the new one.

Bob

[Ed in North Texas]

I shoot the Lee .475-400 bullet in my Martini MkII with good results. Having made a throat cast, I discovered that the as cast diameter of .478 would not be a porblem. I cast them of 1 in 40 tin-lead alloy and double lube with Lee liquid alox. They are a thumb fit in my fired brass (converted 24 gage brass shotshells) eliminating case sizing. I do index them as the breech block on my rifle is not perpendicular to the chamber. I use Ross Siefied's smokless-for-cordite loads with dacron filler. These have about half the recoil of the 480 grain slug and 85 grains of black powder with better accuracy (and no bruises)


Thanks. Apparently I had another CRS moment, the Lee mould is .476-400, not .470. Given your experience with the usually smaller bore Mark II, I guess the .477 Mountain Moulds will not be a problem either. It will be good to get home and get started on working with this rifle (well, when it cools down at home).

P.S. Do you have a URL for the Ross Seifried load? couldn't find it on a search.

[curator]

From an article in "Rifle" magazine about 15 years ago IIRC:

28 grains of IMR 4198 or 25 grains of SR 4759.

Loose-fill dacron batting to bullet base. C-F Ventures wax gas check under bullet. Bullet seated out to touch throat.

I use either of these charges with the Lee .475-400RF bullet in my 2 Martini MkII rifles using fireformed CBC brass. Both of my rifles have good unpitted bores and throats begin at .480+ and taper down to about .468 after about 6 inches. Martini 577-450 throats are really "generous" so soft oversize bullets don't appear to be a problem. Actually, shooting smokeless powder, the larger bullets do not leave any leading in the bore and are much more accurate than bore (.468) diameter slugs.

[The Double D]

Now that is a new one. I haven't seen a .468 bore in a MH before, is this a MK IV?

[Ed in North Texas]

Now that is a new one. I haven't seen a .468 bore in a MH before, is this a MK IV?

Well, from what I've read, I should have stipulated groove, not bore. See:

http://britishmilitariaforums.yuku.com/reply/50140/S-O-G-457-Martini#reply-50140 response by GrantR

There was a response from someone I believe to be you (The Double D) in June (apparently both 6 and 11) 2011 which returns a blank page. The minimal quoting in the search page has the following: ". diameter, 0.465" to 0.467") and Mk IV's ( bore diameter, 0.453" ... groove diameter, 0.470" to 0.472" ... recommended ... No you are not misunderstanding what I wrote, you are only reading what I wrote. The Mark IV's are different and have two different set ... "

I would have liked to read this, but as I stated the search link returns a blank page.

While the topic on the last is just listed as "Re:", I believe it might be related to a thread "CBE MH PP Bevel Base .456 x 480 gn mould (reply)", which also returns blank pages.

Assuming you are one in the same person posting both here and on the Martini forum, I'd appreciate letting me know the accurate diameters (or range if tolerances were typically "broad") for bore, groove, throat and bullet on the Mark IV. Apparently the figure I found from GrantR and elsewhere is wrong. I'm not yet home to slug the rifle, but any help is appreciated.

[Ed in North Texas]

Now that is a new one. I haven't seen a .468 bore in a MH before, is this a MK IV?

Another Senior moment. Because I read the replies as they are posted, I hadn't read the last two (Curator and The Double D) in sequence until just now. Now I see that Douglas was referring to the Curator reply of a .468 bore on the Mark II. I should have caught this based only on the question as to whether it was a Mark IV (because I had stated I had a Mark IV). My apologies to all involved for getting it all bolloxed up.

[The Double D]

If you are seeing blank pages when trying to view British Militaria it may be because you are not logged in.

Yep that's me over there...can't comment on what you posted with out looking at the post...can you provide a lnk,

You may be referring to this post http://britishmilitariaforums.yuku.com/topic/3029/Martini-Henry-bore-groove-dimensions#.Tj6ad4JtySo

Coyote gives a useful list of the dimensions of the bores. Since that post was made, through my own research and testing I have learn that numbers are correct but misleading, not harmfully, but misleading. They do not take into consideration the long large throat.

The throat of the Martini extends 8 inches up the barrel from the breech before the cylinder bore bore starts. This is a long taper that measures .468 in the area directly in front of the chamber in non Mk IV's, then tapers to .464 in the cylinder bore.

The Mk IV's are rebores and larger. You need to slug the bores of these and make a throat casting and measure that to find the right size.

[Ed in North Texas]

If you are seeing blank pages when trying to view British Militaria it may be because you are not logged in.

Yep that's me over there...can't comment on what you posted with out looking at the post...can you provide a lnk,

You may be referring to this post http://britishmilitariaforums.yuku.com/topic/3029/Martini-Henry-bore-groove-dimensions#.Tj6ad4JtySo

Coyote gives a useful list of the dimensions of the bores. Since that post was made, through my own research and testing I have learn that numbers are correct but misleading, not harmfully, but misleading. They do not take into consideration the long large throat.

The throat of the Martini extends 8 inches up the barrel from the breech before the cylinder bore bore starts. This is a long taper that measures .468 in the area directly in front of the chamber in non Mk IV's, then tapers to .464 in the cylinder bore.

The Mk IV's are rebores and larger. You need to slug the bores of these and make a throat casting and measure that to find the right size.


Thanks. The post I was trying to look at was dated June 11, this year. I was logged in, so I guess it was just gremlins. Thanks for the reference, the diagram Coyote posted was also in the post by GrantR which I referred to.

I just bought a Mark IV C and I guess I'll have to wait till I get home (hiding out from the Texas heat right now) to slug it.

Ed

[herbert buckland]

The Mk IV Cs have newly made barells as aposed to the Mk IV A&Bs that are rebored so your rifle should have dementions very simular to the original spects,however I have found that the chambers in these can somtimes acept a much larger bullet than .468.Measure the mouth of a fierd case to get the dementions that fit your chamber properly,I have found for me if the bullet fits the chamber as close as is practical I get better acuracy,the taper in the chamber takes care of sizing the bullet as it goes into the rifling so pressure with BP is no problem no matter the size of the bullet

[Stevie]

The martini bores are tapered. Meaning that the back half of the barrel is large tapering down to nominal bore diameter in the front half of the bore.

I notice my MkIV(B model?) really seems to have less of this taper-bore. I believe it's a re-bored barrel...has two sets of markings on the knox form anyhow.

My MkII rifles shoot .469 bullets well...and so does the MkIV for that matter. However I've not really benchrested the guns to see what the ultimate accuracy is like.

[Red River Rick]

The martini bores are tapered. Meaning that the back half of the barrel is large tapering down to nominal bore diameter in the front half of the bore.

I have yet to see a Martini with a bore that was deliberately manufactured tapered! What your measuring is more than likely due to erosion and not maufactured.

I went and took both of my M-H (MK III, Enfield made) and neither one has a tapered bore. I can drop a 0.449" pin gauge down thru the bore, starting at the chamber and it'll slide right thru. A 0.450" pin gauge will only enter the bore about 2" ahead of the chamber. So, that tells me that there is no taper.

The only barrels, with a tapered bore that I know of, are made via rotary hammer forging. Parker-Hale made their barrels this way. The reason for the taper was to be able to withdraw the mandrel from the barrel.

If I recall, when P-H went under, most of the equipment went to Italy. Some Italian made BPC barrels are tapered and probably made on the old P-H equipment.

RRR

[herbert buckland]

The taper in the Martini Henry bore is from the throat to 8 inches into the bore then there is no taper

[Stevie]

Yes..the bore is tapered....like rifling and all for however many inches in front of the chamber.

Not like they free-bored the barrels the first 8 or 10 inches....that part is rifled too....I would presume it's tapered from whatever diameter down to bore-size.

My MkIV has very little of this 'taper' to it's bore or maybe none...maybe just a couple inches taper.

[herbert buckland]

In the Martini Henry 2.871 inches from the breach the throat is .469 inches and at 8 inches is .45 inches and at 11 inches is .449,groove diameter is .464 inch(larger on converted ,402 barrels I am told) acording to original drawings.The converted Mk IVs A & B models will have slitly larger bore and groove diameters acording to people who have measured them ,but the chambers will be ecentialy the same taper all though the chambers in these rifles vary a lot as well and some comercial 577-450s are repoted with much tighter groove diamerters and no taper in the throat,but I have never seen one of these my self from over 40 years of collecting and shooting this caliber.From these dementions you can see it takes a .468 or larger bullet to fit the throat propery and get the best acuracy from these rifles

[Cap'n Morgan]

I went and took both of my M-H (MK III, Enfield made) and neither one has a tapered bore. I can drop a 0.449" pin gauge down thru the bore, starting at the chamber and it'll slide right thru. A 0.450" pin gauge will only enter the bore about 2" ahead of the chamber. So, that tells me that there is no taper.

Rick.
The reason you didn't find any taper is that the taper is cut in the grooves only. The bore has the same diameter throughout the barrel, but the width of the flats on top of the "lands" diminishes toward the throat in the tapered section. Probably the idea behind the taper was to guide the paper-patched bullet into the rifling without damaging the patch.


Pictures of the Martini Henry rifling:
http://britishmilitariaforums.yuku.com/topic/9655/Henry-rifling-specification

[The Double D]

I have yet to see a Martini with a bore that was deliberately manufactured tapered! What your measuring is more than likely due to erosion and not maufactured.

I went and took both of my M-H (MK III, Enfield made) and neither one has a tapered bore. I can drop a 0.449" pin gauge down thru the bore, starting at the chamber and it'll slide right thru. A 0.450" pin gauge will only enter the bore about 2" ahead of the chamber. So, that tells me that there is no taper.

The only barrels, with a tapered bore that I know of, are made via rotary hammer forging. Parker-Hale made their barrels this way. The reason for the taper was to be able to withdraw the mandrel from the barrel.

If I recall, when P-H went under, most of the equipment went to Italy. Some Italian made BPC barrels are tapered and probably made on the old P-H equipment.

RRR

What are describing is taper and it matches exactly the original gauging letter instructions. Here is the drawing showing the dimensions includng the taper.

http://www.fototime.com/C24DDD0687BA7E3/orig.jpg

I would upload the gauging letter, dated 1880 for these rifles but it is to large for this board.

The letter also mention the toleration and the gauge only passing up two inches is within tolerance. What you have is a rifle with a tight bore that's all.

[Red River Rick]

Gentlemen:

Thanks for the clarification. When the word "Tapered" was mentioned, and no real numbers put forth. I invisioned some sort of taper going from 0.468" to 0.450" over a distance of 8.00"! Like some sort of "SUPER" long throat.

For the slight amount, that the taper actually is, and if one didn't know better (which I didn't), one would assume that little amount would have been machining tolerance, for the time.:oops:

One on the M-H's that I have has a very good bore, almost immaculate except for the first inch from the muzzle. It's a very early Canadian issue, marked M&D on the buttstock (Militia & Defense). So, I doubt that it was used much..........for shooting.

Double D:

Too bad those numbers aren't more legable. It's hard too make them out.

:drinks:
RRR

[The Double D]

http://www.fototime.com/F31238B598E4791/orig.jpg

is this one better?

[Gert Odendaal]

Please upload a full description/drawing of a Martini Henry rifle bore/barrel dimensions ?

[Bad Ass Wallace]

My Martini runs with a 520gn boolit sized to .462". They must have shipped all the large bored ones overseas! :kidding:

http://img.photobucket.com/albums/v152/BAWallace/577_450_50m.jpg (http://smg.photobucket.com/user/BAWallace/media/577_450_50m.jpg.html)