Have any of you had problems while compressing ball powders, such as W760. Norma says ball powder should never be compressed, whereas Nosler offers some loads wherein W760 is compressed.

I've noted that ball powders do not compress much before one gets bullet push-out or case bulging. But, I've never encountered excursions with mildly compressed ball powders.

Your experience?

AIU

I have used W760 and H414 (same powder different distributors) and have never come close to a compressed charge in my '06's. Double base powders can cause problems in compressed charges. One problem is with failure to ignite (they typically use magnum primers) and the other problem is that with the nitroglycerine base they can, under the right (or wrong) circumstances, detonate. The warnings about compressing these powders has been around for more than 40 years so I stay clear of compressed loads with double base powders. I have seen a few compressed loads printed but I will continue to stay away from them.

As long as the powder is not known to spike in pressure, Ball powder can be compressed. I do it all of the time in several of my larger bore rifles to achieve a 100% case load density with no problems.
Like stick powders it depends on the burn rate and the powder composition. I know that a triple base powder does not like to be compressed.

Long term they'll clump. Keep it fresh -- 2 cents.

I have bad experiences with compressed charges of W760 and one of the old Hogdon powders I used in the .222 (don't remember the no.). When the ammo was less than a year or two old the loads worked great and I shot hundreds of rounds so loaded. Then I left a couple of boxes sit on the shelf for 5 years of so and ran into real pressure problems. When I broke down the remaining ammo (only took 1 round to determine that I had a serious problem) the powder had to be scraped out of the case. It came out in big clumps looking as if all the grains had fused together. I have never had this problem with stick powders or the old H450 or H110.
C.G.B.

I might have read not to compress ball powder. Might not have is also a possibility but I recall it is the former. Maybe.

I use WC 860 (AA 8700) in two 7 MM Remington magnums. The load is 79 grains behind the original Nosler 162-grain Solid Bases. That powder charge is almost flush with the neck, so it goes without saying that the charge is very compressed when the bullet is seated.

I use Federal 215s to ignite the charge, and I have to this point had nothing but excellent results. I don't care about velocity, but I do care about groups, and in both the Tang Safety Ruger 77 and the Remington 700, this load will shoot clover leafs if I do my part.

quote:

Originally posted by cgbach:
I have bad experiences with compressed charges of W760 and one of the old Hogdon powders I used in the .222 (don't remember the no.). When the ammo was less than a year or two old the loads worked great and I shot hundreds of rounds so loaded. Then I left a couple of boxes sit on the shelf for 5 years of so and ran into real pressure problems. When I broke down the remaining ammo (only took 1 round to determine that I had a serious problem) the powder had to be scraped out of the case. It came out in big clumps looking as if all the grains had fused together. I have never had this problem with stick powders or the old H450 or H110.
C.G.B.

Thanks for the replies guys - I appreciate it.

I've also had problems with clumped/fused powder grains with marked compression and long-time storage, especially with Norma MRP, but never with a ball powder. The clumped/fused MRP caused excessive pressure and reduced velocity. Thus, I agree long-time storage of compressed powder is not a good idea and fresh reloads are best.

IMO, compression of extruded powder is OK and Norma clearly states in their manual..."Extruded powder can be compressed without problems since the initial gases will always find space within the granules and between them." Most Normal powders are double based. They do not like compressing ball powders.

With the exception of long-time storage of compressed MRP, I've had no problems compressing either extruded or ball powder. BUT, IMO caution is indicated compressing ball powders.

Regards, AIU

The problem with compressing a ball powder is that there's just not much "elasticity" (or "crush") there as in stick powders. I've used WC-872 (a ball powder) in a .264 magnum for years in a slightly compressed load with absolutely no problems, but if a load is compressed to the point that either the case bulges (an obvious problem) or the bullet has to be crimped to keep it from backing out, then there is simply too much compression. Ball powders will reach this point more quickly than stick powders.

To expand on what Normal claims, the following is what they write (see Norma Reloading Manual, 2013, pages 100 and 101)…

“…One of the disadvantages of a ball powder is that it must not be compressed. There must always be a small air gap between the powder and the projectile into which the initially generated gases expand. If the charge is compressed there can be pressure waves within it, of such a magnitude as to damage the weapon. Extruded powder can be compressed without any problems since the initial gases will always find space within the granules and between them. With ball powder the charge will be dense because it is compressed, and when ignited the charge will be driven, more or less, like a piston.

An additional disadvantage of ball powder, as compared with extruded powder, is its ballistic instability – ball powder ages. Ball powder loaded ammunition cannot be stored as long as ammunition loaded with extruded powder. Ammunition loaded with ball powder and stored for long periods of time must be periodically checked; and, if it shows signs of excessive pressure increase, it must be destroyed. This is not necessary for ammunition loaded with extruded powder…”

Also, Normal shows data wherein significant changes occur with increased pressure and decreased velocity within 10 to 15 weeks after loading ball powder.

IMO, it is important that Normal – so far as I know – does not market a ball powder, only extruded powders.

I’m a bit skeptical of some of Norma’s claims, although Norma is not "chopped liver."

Certainly, Winchester would have discovered the poor longevity of stored ball powders long before now, especially given that they extensively use and market ball powders, such as W760 and W780.

When I encountered high pressure + low velocity from long-time stored (years old) compressed Normal MRP loads, I noted that the powder had become “fused” within the case requiring scrapping to remove. I assume under these conditions the hardened “fused” powder was driving forward as a column creating an unnatural burning geometry and increased burn rate. I got flattened primers with loose primer pockets. I unloaded all the ammo and no longer store ammo for long periods – I reload fresh each hunting season.

Your thoughts?

Regards, AIU

Well, I must be flirting with danger every time I load my 375 Weatherby, I run heavily compressed loads of 760 with every load. In fact, I once had to pull some bullets on these loads and discovered the powder was so compressed I had to use a steel scribe to break the powder up to get it out of the case.
I've never had any pressure excursions using these heavily compressed loads and saw no problems on my Pressure Trace II either, pressure rose normally.
I also use heavily compressed loads with a lot of stick type double base powders with no ill effects and will continue to do so because I have never seen any reason not to.
I think a lot of these 'one offs' that occurred in the past for these warnings were just that, one offs from the factories experimenting with powders that were not suitable for the cartridges chosen.
It still happens to this day because internal ballistics is not an exact science and never will be.

Cheers.

Also, I've had no problems with heavily compressed W760 or Ramshot Hunter.

Norma does not indicate which ball powder specifically that caused the above problems - they just refer to ball powder generically.

Anybody else want to share their experience?

See, I thought I read not to compress ball powders.

I loaded 2000-MR in a highly compressed load in June of 2011. I fired some in June of 2013 and found no problems. I will fire some more this June and chronograph it.

"do not compress ball powder" has been a "rule" every since I began reloading. I've never questioned it. And I'm not one to do something "just because I can". If I'm close to compressing a ball powder or even a stick powder load, I just go to another powder. It's not like we don't have enough diversity in powder burn rates to do that.

I know. lots of guys do it. I don't and I am not a particularly conservative loader.

quote:

Originally posted by wasbeeman:
"do not compress ball powder" has been a "rule" every since I began reloading. I've never questioned it. And I'm not one to do something "just because I can". If I'm close to compressing a ball powder or even a stick powder load, I just go to another powder. It's not like we don't have enough diversity in powder burn rates to do that.

To each his own. My nearly fifty years of experience in handloading, the last forty-plus of which I've owned a chronograph, have shown me that powder with burn rates which are slightly on the slow side for a cartridge/bullet combination and which therefore require slight compression almost always result in more consistent velocities (and presumably pressures.)

I would agree that since Norma doesn't market any "ball" powders (and makes none -- all of theirs is purchased from Bofors), that it seems odd that they would have the experience, much less the standing, to comment on the loading of such powders.

As I said earlier, ball powders are not as compressible as stick powders, so one reaches the point of excessive compression with ball powders when the case is not quite as full as with stick powders.

The first warning I ever saw about compressing ball powders was in the Winchester load book.

The grains are ball shaped for most rifle powders and flattened ball shapes for most pistol powders. The flattening of the balls is the last step in controlling the burn rate of the powder. It compresses easily and if that alteration increases the burning speed you could end up with pressure increases. I have heard that when the volume of ball powders takes up all the room in a cartridge (without compression) it is more difficult to ignite and thus those loadings recommend magnum primers.

If you are using published load data that utilizes compressed charges then I would assume that it has been tested and is safe under the test conditions. If you are experimenting on your own then please be careful. Remember that ball powders (all double base powders) use nitroglycerine as well as nitrocellulose and are prone to certain problems that single base powders are immune to. One of these is that under extreme cold double base powders will detonate because the nitroglycerine freezes and becomes very unstable.