.32SWL detonation

[madmax]

We have been working up a variety of loads with a .32 SWL semi-auto using 98gn HBWC projectiles. The idea is to see how light the loads can be and maintain acceptable group sizes with reliability of function. We got as low as 0.8gn N310 before the pistol began to malfunction. Some members in our Club mentioned that if the loads become too low, then the powder will detonate, rather than burn, resulting in all sorts of mayhem to the pistol and perhaps the shooter. All comments are anecdotal, as no-one has actually seen this happen, or know directly of anyone it has happened to. I'm curious to know if this is a fact, but I'm not intending to load below 0.9gn, which gives good accuracy, no malfunctions, and less recoil than a .22.

Thanks. Max.

[Popeye]

Max - So which load of N310 has given you the BEST accuracy? I suspect "best" accuracy may be a minimum of about 1.1gr but I haven't tried to experiment in the range like you have done!

The recoil doesn't matter with Centrefire matches.

Popeye

[BEA]

The detonation theory has not been proven. This theory has been brought to light in recent years primarily because of the cowboy action shooters blowing guns up. Since they typically use such low charge wts, I think most of these failures are due to multiple charges rather than too little powder. Unfortunately, after the gun is destroyed, it is hard to know why. In their quest for low recoil, they are using very small powder charges in big cases such as the 45 Colt. The best protection is not push the envelope too hard.

[Rover]

The NRA investigated this many years ago. Their finding was that blowups were caused by double charging of the cartridge in pistol loads.

In many years of shooting I have never seen even a double charge blowup much less a "detonation".

I have a fair amount of experimenting with very light pistol powder loads in hunting rifles for small game hunting with no problems. I HAVE seen excessive charges blow pieces off some rifles.

[ColinC]

For what it's worth check http://home.winsoft.net.au/gazza/DISASTERS.htm

[orionshooter]

? . . but I'm not intending to load below 0.9gn, which gives good accuracy, no malfunctions, and less recoil than a .22.

Thanks. Max.

Can you Quantify what you mean by good accuracy ( both in terms of group size and distance)?

[mika]

With a fast powder like N310 and a small case like .32 S&W Long, I wouldn't worry much. My understanding is that the detonation problems are rather related to situations with a case relatively large compared to the actual load and that the risk is higher with slower powders. N310 and N320 are used for subsonic rifle loads in 7,62x39 and .308 Win, loads well under 10 grains.

Small charges as such are not a problem. Just think about .22 Short.

Mika

[David M]

A number of pistols have been damaged in the past, and some powders have been removed from sale or modified to change burn rate.
The problem appears to be with very small charges and excessive case capacity.
It is to do with the way the primer flame ignites the charge if it lays along a long case with a large surface area.
Play with small charges, but try seating the projectile down into the case to reduce the available airspace.
You can also try using a bulkier powder to fill the airspace ie Trailboss.

[Mike M.]

Another option to consider is loading the powder with a filler. I've heard of people using a bit of pillow filler (some sort of polyester fiber, IIRC) as a filler.

There's also the old black powder shooter's standby, Cream of Wheat.

[Tycho]

AFAIK, the "detonation" is only a issue with light .38 loads, not with .32

[Gwhite]

Another option to consider is loading the powder with a filler. I've heard of people using a bit of pillow filler (some sort of polyester fiber, IIRC) as a filler.

Do NOT use polyester filler. It tends to melt & will gunk up your bore over time. Cotton works better.

[mika]

Another option to consider is loading the powder with a filler. I've heard of people using a bit of pillow filler (some sort of polyester fiber, IIRC) as a filler.

Do NOT use polyester filler. It tends to melt & will gunk up your bore over time. Cotton works better.

Dacron (polyester) works great as a case filler over small powder charges. It actually doesn't melt or burn, at least completely, the wads end up on the ground in front of the shooter. Or in the suppressor, if your gun has one. As mentioned, the wads are sometimes used for subsonic loads in normal size rifle cases with very light loads of pistol powders, and the common use for these is to avoid muzzle blast and noise in suppressed guns. Some suppressors are rather difficult to clean.

Mika

[buonvento]

Do you think that a filler can help to improve burning a so small amount of powder in a cartridge case so big? Does anyone use it?

[mika]

Do you think that a filler can help to improve burning a so small amount of powder in a cartridge case so big? Does anyone use it?

A case so big? .32 S&W Long is one of the smallest cases people routinely reload. It's kind of long if you compare it to 9x19 or similar traditional pistol rounds, but the bullets usually used for target shooting are wadcutters and seated fully in the case, so there is little room for powder. Even with the hollow base wc's, the actual volume behind the bullet is very small. I don't think a filler would really change anything, you'd just leave more trash at the range.

No, I don't use a filler in .32. I have to admit that I don't even reload that cartridge (yet). But I do use fillers in other cartridges, mostly subsonic rifle rounds, and it kind of helps, gives a bit more repeatability, but mostly it's not really that big difference. 7-20 grains of pistol powders (like N310, DO NOT USE THIS AS A LOAD RECIPE!!!) in cases as big as 7,62x39, .308 Win or 7,62x53R works with or without fillers. Another application is blackpowder revolver, there cream of wheat fills the space between a small powder charge and the bullet (often a round ball). With BP, it's very important not to leave empty space between the powder charge and the bullet, and with the loads I use, the bullet would have to be seated very deep in the cylinder, making it diffcult to seal with grease. It's also more accurate with less free flight before engaging the rifling, but I guess this is digressing too far from the olympic pistol shooting...

Mika

[Rover]

Please allow me to be blunt.

This detonation stuff is just a pile of Internet crap.

Load as light as you please. You won't have problems.

[buonvento]

Case = about 20 mm.
Bullet = about 14 mm.
Powder = about 4 mm.
I agree, no filler...

[madmax]

Thanks for your replies guys - look at the number of 'hits'!!

The original enquiry appears to bring out the 2 exttremes - but the tendency is for no detonation in a case with small volume.

Some of the results of the experiment - sorry, we have already thrown out all the targets. We shot 30 combinations of 10 shots each from an MG4. 2 projectiles, 98gn HBWC ( Tiapan, Australia and Hornady, US). Powder was N310 in 5 x 0.1gn increments from 0.8gn to 1.2gn. # primers used, Federal Small Pistol, Federal Small Pistol Magnum, Federal Small Rifle. This started out as an experiment on the primers following an earlier posting on the use of these primers.

Best group was 24mm from 1.1gn N310 with Taipan projectile, giving an average of 600fps.

As for the wadding? Tried variouse loads in .32SWL some years ago, using cream of wheat as a filler - just like the BP shooters do. They didn't ignite. When pulled apart, the powder immediately in front of the flash hole was burnt, but the rest of the powder failed to ignite.

Material for some more comments????

Thanks again.

Max.

[madmax]

HI Sorry, but I forgot something.

Using the velocities from the Small Pistol primers as a base. velocities from both the Small Pistol Magnum and Small Rifle primers were close to being the same (negligible difference) and approximately 5% higher than the Small Pistol primers. We're staying with the Small Pistol primers as they were a little more consistent with velocity variations.

Max.

[mika]

As for the wadding? Tried variouse loads in .32SWL some years ago, using cream of wheat as a filler - just like the BP shooters do. They didn't ignite. When pulled apart, the powder immediately in front of the flash hole was burnt, but the rest of the powder failed to ignite.

Material for some more comments????

I've never heard anyone else trying cream of wheat as a filler for smokeless cartridge loads. Also for BP guns, it's always compressed on top of the powder and under the bullet, so it won't mix. I guess in a cartridge, if it could work, it would have to be a compressed load with no mixing. Anyway, I don't see any need for a filler in .32 S&W Long, small or hot loads.

Mika

[DukeShooter]

Performance of smokeless powders is a complex subject. Smokeless is a propellant and as such the burning rate can change if it is compressed thus impacting the pressure curve during ignition.

Also, if you have a small volume of powder in a large open space the problem becomes keeping ignition consistent. By placing wadding in your cartridge forcing the powder grains close together against the primer gives more consistent ignition and resultant pressure curve consistency.

Now having said all that BS, I highly recommend experimentation, thats what makes reloading fun! I spent all last fall developing my hunting load and after much work I can now drop 5 shots in a hole smaller than a dime (its a 25-06) at 100 yards from the bench.

Keep experimenting!