Compression in a bottle neck rifle cartridge

[Gunfreak25]

I was told that you should never compress your BP in bottle necked cartridges, as it will lead to inaccuracy. Anyone ever heard this? The cartridge i'm loading for is 11.15x60r.

[JeffinNZ]

I heard and read you should not compress Swiss powder as it does not shoot well. My .38 BPCR rifle LOVES 1.5Fg compress 0.35 inch.

Try it and see.

[powderburnerr]

I like to have enough powder in the case to fill part of the neck then I compress enough to get close to the bottom of the neck ,but stop before I reach it then go from there .mostly just enough to ensure no settling of contents....Dean

[martinibelgian]

Little to no compression is best - so a bit can be useful, but you don't need to horse down on the powder, that will only worsen the outcome...
11.15 x 60R ? that the old 450/40 BN BPE case. It can and will shoot well with BP.

[405]

Ya, I've always wondered about it. I load three different BN BP rounds. 43 Spanish, 45-75 and 44-90BN. I never load more than 15 or 20 at a time and most times just 5 or 10 so the tedious nature of BPCR loading doesn't bother me too much.... it's all part of crafting unique, interesting ammo. Specifically, I've wondered about BN and black due to the nature of blackpowder at ignition where the compressed slug of BP at and going thru the shoulder constriction could cause erratic pressure. After a lot of shooting of these I still don't know the answer. In two of them where I shoot some smokeless also I can tell no accuracy (or velocity SD) difference between the BN cartridges and their straight-walled cousins.

For BP I load primarily Goex 2F. Fill to about half neck level and never lower than shoulder/neck transition. I use a drop tube. Then, just tap carts in loading block to settle powder as much as it will. Then lightly compress to no lower than junction of neck and shoulder (maybe 1/8" compression or less). Top with wad and bullet (and grease cookie if shooting PP bullet). That's about it.

[kodiak1]

What 405 has stated is pretty much the same way I do it with my 40-90 SBN. I shoots pretty fair. If I took the time to really work on it then the performance would probably be better.
I shoot for fun and can get a 2" group with it at twoo hundred yards, so good enough for me.
I can hit the buffalo gong that we shoot at at 450 Yards with killing shots once I get myself and the rifle adjusted.
Ken.

[Baron von Trollwhack]

When I was shooting 43 Mauser, 71/84, for many years, I found that it shot noticeably better with the bullet seated firmly on the powder, but not to the extent of compression. No need to crimp. This was with ffG, duplexed ffg, and fg, patched or GG, soft or hard bullet. I believe that is the general consensus of all I have read. BvT

[The Double D]

The question is how do you uniformlyu compress a load that is wider than the neck through which you can insert the compression tool.

My favorite example is my 577.450. .45 cal neck and .577 powder chamber.

[Baron von Trollwhack]

Well of course you cannot uniformly compress a load in those bottlenecks. Best you can do for uniformity is to drop tube and seat the bullet snugly above the shoulder. BvT

[martinibelgian]

Believe me,

The last thing you want to do in 577-450 is to droptube powder - better pour it straight in: that way a smaller amount of powder will take up more space - and contrary to 45-70, 577-450 has LOTS of space available. More than you'll ever want to use... It would be relatively easy to get about 120grs of Fg in that cavernous case!

[Baron von Trollwhack]

I guess those imperial Tommies were tough, especially the carbine shooters.

BvT

[405]

Believe me,

The last thing you want to do in 577-450 is to droptube powder - better pour it straight in: that way a smaller amount of powder will take up more space - and contrary to 45-70, 577-450 has LOTS of space available. More than you'll ever want to use... It would be relatively easy to get about 120grs of Fg in that cavernous case!

Without talking about compression, I'm curious about getting 120 gr of 1F in the case to the bottom of neck by drop tubing when the basic 1F charge for this cartridge is 80-85 gr. ?? unless that is a different 1F or if an air space was a given for the standard load ??

The most "extra" I get out of drop tubing in other average BP rifle cases (including some large capacity ones) is a few grains at most. The one thing that drop tubing does for my loading is it pre-settles the charge so that after the bullet is seated on top of the charge any subsequent handling, bumping, etc. won't further settle the charge thus leaving an airspace between charge and bottom of bullet. Simply pouring a BP charge in a large rifle case, especially a bottle neck type, then seating a bullet on top would also seem to increase the variability of the air space due to settling. My thinking in all this is based on consistent ballistics and accuracy and not a way to increase or decrease charge or recoil by the way the powder is put into the case.

[Baron von Trollwhack]

Several issues of the "Cartridges of the World" or older "Gun Digest" books showed the arsenal drawings for the 577-450 on the inside back cover. I recall that a thick wad was at the base of the neck, then a wax disc, another thick wad, a hard card wad, then the bullet. Perhaps some googling can turn up those illustrations again, and provide an original insight.

Bvt

[martinibelgian]

Believe, accuracy is MUCH better with a reduced loads compared to a full case - and not only because of recoil. Shooting a military issue Martini is not like shooting a BP match rifle, trying to squeeze every bit of accuracy from it.
BTW, how would the powder settle? Just taking a round out of the box and loading it would - again - rearrange things, as would transport and any handling of the ammo...
BTW, don't forget the original load was a foil case, seriously undersize, with thick base . With modern, drawn brass, 577-450 is overbore - it can hold more powder than it is efficiently and accurately able to use. FWIW, I also use Swiss Fg - which could be less bulky than some other Fg powders.

[405]

If powder won't settle then drop tubing won't change an 80 gr capactiy case into a 120 grain capacity case.

[Lead pot]

Believe, accuracy is MUCH better with a reduced loads compared to a full case - and not only because of recoil. Shooting a military issue Martini is not like shooting a BP match rifle, trying to squeeze every bit of accuracy from it.
BTW, how would the powder settle? Just taking a round out of the box and loading it would - again - rearrange things, as would transport and any handling of the ammo...
BTW, don't forget the original load was a foil case, seriously undersize, with thick base . With modern, drawn brass, 577-450 is overbore - it can hold more powder than it is efficiently and accurately able to use. FWIW, I also use Swiss Fg - which could be less bulky than some other Fg powders.

You are right.
I shoot the bottle neck cases, now I'm talking black powder.
A black powder load in the bottle necked case is much more consistent than a compressed load.
The ES and SD is much lower with a loose powder load and so is the velocity.
But the bottle neck does increase the velocity some were the straight walled case will not with the same powder load and bullet weight.
My load gets .100 compression just enough thet the wad does not settle during transport when the cartridges are rattling in the box.
A loose powder load in the straight case also is more consistent than a heavy compressed load.
I get the best accuracy with the case filled just short of compressing and without using a wad with black powder.
Yes the load is slower and in most cases the fouling is a little heaver but that fouling can be controlled .

Lp.

[martinibelgian]

405, then why droptube if there's no need for it? Just because isn't a reason in my book... Just shovel it in, it doesn't matter anyway...
Powder WILL settle with droptubing, even if it's a temporary condition. I too use a droptube for 45-70, so that I can get 80grs of powder in (together with some compression...)

[Boz330]

If powder won't settle then drop tubing won't change an 80 gr capactiy case into a 120 grain capacity case.

405, the original load was a brass foil case with 85 gr of 1F with carded wool as a filler. The case was well under size as MB pointed out. The base was also iron I beleive, sort of like a shotgun base, so it took up a lot of room in the base.
577-450 cases can be formed from Magtec 24ga brass shot gun cases and I have measured 115gr loads of 1F in those cases loose. Considering the diameter of the case 120 would be well within the realm of possibility with a drop tube.
The Bertram brass and the Jamison brass will take 95gr to 100 gr with out to much problem.
A load that works good in my rifle is 70gr of 1.5F swiss with an active filler ( 50-50 mixture of cream of wheat and 3F Swiss mixed). I have also tried cannon grade which works really well for about 4 shots and then fouling gets severe, 95gr. I have also tried kapok to fill the case but accuracy isn't as good and you have all this confette floating around.
As far as the Martini carbine they flat ass hurt with loads for the rifle.

Bob

[405]

This thread has wandered from the basic question about compression in a BP BN, specifically the 11.15x60R, to a discussion about the case capacity of the various? 577 based BP cartridges???

Seems like two theories have emerged.
1) settle (or drop tube) black powder in BN case to no lower than bottom of neck then seat bullet on charge column with low to little compression.
2) pour powder in, seat bullet.

Depending on the volume and shape of the case, I've found that if BP is just poured in, then bullet seated on top.... there WILL BE some settling.... leaving an air space between powder and base of bullet. I have also found that either by drop tubing or by tapping case lightly after filling, the powder will settle to a point at which it resists further settling. I've also found that this settling by tapping or drop tubing will not add more than a few grains of powder to the overall charge. I've found that the only way to add significant amount of charge to a case is by compression.

I do not leave any air space between charge and base of bullet in any of my BP loads be they straight-walled or bottleneck. I do not use filler or wads in any of the BP BN carts where the filler or wads seat below the bottom of neck. I have not damaged or rung the chamber in any gun I've loaded for. My loads tend to be very consistent and accurate. I shoot guns ranging in age from 135 years old to modern.

The other theory (2) must be (and I've read it on this forum several times) that there is little concern about air space between BP charge and bullet base. I have no way to prove or disprove that theory without testing it on one of my guns... I think I'll pass on that experiment :)

As for capacity of the 577 based cases? Yes, they are very large indeed. I imagine there was a reason that the normal charges ran about 80-85 grains. The charges were not regulated by the choice of whether or not to settle or drop tube the charge! (Compression is not the same thing as settling or drop tubing.) The charges were regulated by a base wad (shotshell like?), loose over powder wad or a liner. Seems like if they were not concerned about leaving an air space in the case between the charge and the bullet base they would've simply poured in the desired charge (60, 70, 80, 90, 100 grains or whatever), seated the bullet and ignored the air space whatever it ended up being. I don't own a 577 based BP gun so... how those specific types are loaded today I have no experience.

[martinibelgian]

405,

After reading W.W. Greener advocating the use of partially charged cases with airspace, I put it to the test - lo and behold, no ringing, no exploded barrels, no curse descending upon me...
Of course, best accuracy is usually obtained with cartridges allowing the use of a powder charge requiring slight compression to seat the bullet - but when shooting vintage military rifles, sometimes you don't have a choice...

Let me rephrase that: you either shoot 100-120grs of powder in that 9-pound rifle, or a more reasonable charge with some airspace or filler (NOT a wad, a filler - something completely filling the space between bullet and powder charge). I have found that the 'airspace' loads will perform pretty well - better than one could hope for. And I also found out - unsurprisingly - that W.W. Greener was right: shooting charges with some airspace will not hurt the rifle. mind you, I limit myself to loads where the total volume consists of at least 70% powder, of the appropriate granulation (if you want to shoot 30grs of FFFFg in 577-450, that's your problem).


Some things are repeated on the 'net like a mantra, and everyone assumes it is so - when in actual fact, there is no truth to it. Well, maybe a partial truth in some cases, but no absolutes as we're led to believe.
And there's more knowledge as yet undiscovered, just because we don't make the effort/take the time to read the documents of the BP era - maybe we're just choosing to ignore them? After all, there's no need to reinvent hot water...

[martinibelgian]

405,

After reading W.W. Greener advocating the use of partially charged cases with airspace, I put it to the test - lo and behold, no ringing, no exploded barrels, no curse descending upon me...
Of course, best accuracy is usually obtained with cartridges allowing the use of a powder charge requiring slight compression to seat the bullet - but when shooting vintage military rifles, sometimes you don't have a choice...

Let me rephrase that: you either shoot 100-120grs of powder in that 9-pound rifle, or a more reasonable charge with some airspace or filler (NOT a wad, a filler - something completely filling the space between bullet and powder charge). I have found that the 'airspace' loads will perform pretty well - better than one could hope for. And I also found out - unsurprisingly - that W.W. Greener was right: shooting charges with some airspace will not hurt the rifle. mind you, I limit myself to loads where the total volume consists of at least 70% powder, of the appropriate granulation (if you want to shoot 30grs of FFFFg in 577-450, that's your problem).


Some things are repeated on the 'net like a mantra, and everyone assumes it is so - when in actual fact, there is no truth to it. Well, maybe a partial truth in some cases, but no absolutes as we're led to believe.
And there's more knowledge as yet undiscovered, just because we don't make the effort/take the time to read the documents of the BP era - maybe we're just choosing to ignore them? After all, there's no need to reinvent hot water...

[Cap'n Morgan]

Seems like if they were not concerned about leaving an air space in the case between the charge and the bullet base they would've simply poured in the desired charge (60, 70, 80, 90, 100 grains or whatever), seated the bullet and ignored the air space whatever it ended up being. I don't own a 577 based BP gun so... how those specific types are loaded today I have no experience.

Maybe Her Majesty's Armed Forces were worried the powder granules would break down over time - through transport and rough handling - creating dangerous pressures?