Small pistol primer brisance:

["Big Boston"]

Addendum: A while after conducting my tests, I happened upon an article about testing Large Rifle primers, different brands, standard and magnum. It's a good read, and provides some theory and science behind primers and testing brisance. The article ranks primers in order of the velocity obtained, Es (Extreme spread) and Sd (Standard deviation) and explains the terms. Here's the link  http://www.targetshooter.co.uk/?paged=10&cat=58

 

My tests follow the same methodology, albeit less scientific, with smaller sample sizes, and no group testing. 

 

Also; Since completing these tests I have tested another 38 Spl loading, this time with Tin Star. It is the listed starting load, and although a bit faster than I'd like, it looks promising. I am planing to repeat my primer test, this time using Tin Star. The factory describes Tin Star as being easy to ignite, to that end, my preliminary load was with a S&B SP primer.

 

Here are my preliminary test results.

 

In my New Vaquero 

Velocity Av

842/846

Es

29.3/14

Sd

11.7/6.3

Shots

5>/5<

 

In my '66 Cimarron

Velocity Av

1004

Es

27

Sd

9.6

Shots

9

Pressure signs were similar to the Trail Boss load, but it burnt cleaner IMHO.

 

BB

 

 

It would be nice if there were some definitive tests for the relative brisance of the various small pistol primers. During load testing I discovered that changing the make and model of the primer had an influence on the load; velocity and consistency. 

 

My stash of WW 452AA powder is rapidly dwindling, I'm down to a couple of tablespoons of the long ago discontinued powder. In a way I should be celebrating, the stuff has been hogging a corner of my powder magazine for years. The quest for an application eventually yielded a couple of pretty decent loads for the 38 special and the 357 Magnum. 

 

With the 452AA end nearing, so began the quest for a replacement load. 

 

I believe it was on this forum I originally saw a load testing, chronograph, suggestion. That being, to chronograph each load, powder forward and powder rearward. The results of that method of chrono testing a load are interesting to say the least. 

 

Finding a replacement for 452AA should be fairly easy. After all, there are about a dozen or more candidates. My target load is for my '66 Cimarron in 38 Spl. My bullet is a 147 grain Xmetal bullet coated with Hi-Tech. I seat for an OAL of 1.5" for reliable feeding. One less variable. The only variables being the powder and primer. 

 

I used my Vaquero in 357 for chrono testing, easier to control powder position, and if the load proved to be a bit high in pressure for use in my '66, it is pretty unlikely that my Vaquero in 357 Mag would even notice.

 

I began with Hodgdon Universal and a CCI 500:

 

Velocity Av

790/816

Es

65/37

Sd

25/13.5

Shots

5>/5<

 

Changing to a Fed 100 got me this:

 

Velocity Av

798/839

Es

50/38

Sd

19/37

Shots

5>/5<

 

A WSP (Winchester Small Pistol) got me this.

 

Velocity Av

806/840

Es

23/75

Sd

10/28.5

Shots

5>/5<

 

I do have some S&B SP primers, so I gave them a whirl as well.

 

Velocity Av

771/805

Es

38/54

Sd

16/22

Shots

5>/5<

 

For these primers, with Hodgdons Universal I would rate the brisance of these primers thus:

 

1: S&B SP, the mildest in brisance.

2: CCI 500, the next stronger primer.

3: Fed 100.

4: WSP, the primer with the most brisance.

 

BTW, the definition:

"Brisance /bri'za:ns/ is the shattering capability of a high explosive, determined mainly by its detonation pressure. The term can be traced from the French verb "briser" (to break or shatter) ultimately derived from the Celtic word "brissim" (to break)."

 

Brisance seems to be only one part of the equation. There must be other factors or variables that influence the consistency of igniting the powder. Unfortunately the only way to try and limit the powder forward/rearward velocity variations is by trial and error. Sometimes, the results from all the different primer combinations will be mediocre, and one either lives with the mediocrity or tries another powder. 

 

I looked at my files, loading records, and one particular load with Trail Boss looked intriguing. The chrono figures were from before I started testing powder forward/rearward but the Es/Sd #'s were decent. 

 

From experience I know that Trail Boss likes a fairly hot primer, and the WSP is the primer Hodgdon has in their data, so I stated there. Unfortunately, they do not have data for a 146 gr lead bullet, so a bit of interpolation was in order.

 

I'll list the results as they address the consistency or lack of consistent velocities for forward/rearward powder ignition.

 

My first 38 special handload with Trail Boss powder was promising, but not real good. The primer was a WSP.
 

Velocity Av

707/728

Es

51/24

Sd

18.5/9

Shots

5</5>

I increased the powder charge first, which improved things a bit.
 

Velocity Av

776/777

Es

45/27

Sd

17.5/12

Shots

5>/5<

The powder forward was not as good as the powder rearward, but the velocities were nearly identical. Trail Boss seems to work best at the higher loading densities. I repeated the test with a Winchester Small Pistol Magnum primer.
 

Velocity Av

802/802

Es

19/35

Sd

7.25/13

Shots

5>/5<

As I predicted, there was a velocity increase. More importantly, the powder forward readings improved, and powder rearward didn't change much.

This load is for my '66 rifle, primer thickness is not an issue. My '66 has a fairly solid primer strike. IIRC, the primer cup is the same, just more priming compound.

I tested the load in my rifle, here are the results. (No powder forward/rearward test as a rifle does not get drawn from the holster, and the first round gets cycled from the magazine, I think the powder is pretty much jostled about before firing.)
 

Velocity Av

929

Es

28

Sd

9.5

Shots

10

Because of the fast(ish) burning rate of Trail Boss the velocity increase was small, only about 125fps. going from a 5.5" revolver barrel to an 18" rifle barrel. The report is on the quiet side, and I can easily hear the hits on steel, the hits actually seemed louder than the bang. My goal was for a rifle load that is subsonic, and I'm well under the speed of sound (1200 fps). It does shoot a bit dirty, not filthy, but there is a bit of smoke on the case and residue in the barrel. Easily cleaned out with a wet patch of Hoppes #9.

 

I'm happy with the load, it's only slightly slower than my old load, and the Es/Sd #'s are better. Best of all, Trail Boss is still in production.

 

Anyways, just a FYI post. But if anyone knows of a published, scientific brisance test of small pistol primers, please let me know.

 

BTW, building a larger primer storage unit is on the to-do list. I think I now stock around 8 different small pistol primers. Some of the cheaper off shore small rifle primers work well, sometimes.

 

My testing of large pistol primers in the 44 Spl/Mag is a work in progress, but initial results show the same forward/rearward anomalies. 

 

Big Boston

 

PS: For S&G it tested some factory 38 Spl. 40 fps difference doesn't impress me. 

 

Velocity Av

756/796

Es

24/38

Sd

15/15

Shots

5>/5<

 

My Chrony has always been rather generous with the velocity #'s, YMMV.

 

 

My 38 Spl ammo.

 

[Assassin]

What was the temperature when you did your testing? And, was the ammo in the sun or shade?

[Garrison Joe, SASS #60708]

Winchester WST is the functional cousin of their old 452AA powder.   I find they load to the same weight and performance in 12 gauge shotgun shells.  And it makes a nice pistol powder, perhaps slightly more expensive than the cheapest out there, but it's certainly cheaper and cleaner than Trail Boss.

 

I understand your description above, but I certainly would not put that much work into making up a Cowboy revolver load. 

 

Good luck, GJ

[Badlands Bob #61228]

I think the most important thing is to find a bullet type and OAL that feeds well in the rifle.  Don't over think this.  It's not that hard.  

[Duffield, SASS #23454]

When accuracy testing for my .220 Swifts, 30-06 and .243s, I learned that primers vary as much from one lot to another as from brand to brand.

I don't worry too much about primers for our game, but if I did I would buy a HUGE amount of the same lot number.

 

Duffield

["Big Boston"]

7 hours ago, Garrison Joe, SASS #60708 said:

Winchester WST is the functional cousin of their old 452AA powder.   I find they load to the same weight and performance in 12 gauge shotgun shells.  And it makes a nice pistol powder, perhaps slightly more expensive than the cheapest out there, but it's certainly cheaper and cleaner than Trail Boss.

 

I understand your description above, but I certainly would not put that much work into making up a Cowboy revolver load. 

 

Good luck, GJ

I did try WST, I liked the clean burning, but wasn't able to overcome the powder position sensitivity. 

 

Velocity Av

756 /820

Es

37/55

Sd

13.8/23

Shots

5>/5<

 

This is a test in the 357. The same charge by weight and the same primer as my 452AA load.

 

Velocity Av

783.4/787

Es

25.2/22.3

Sd

9.9/9.5

Shots

5/5

 

That is my 38 Spl load with 452AA.

 

Velocity Av

835/838

Es

25.2/71

Sd

10.5/36

Shots

5/5

 

This is my 357 Mag load with 452AA powder and with a CCI 500 primer.

 

Velocity Av

844.7/835

Es

21.5/25.1

Sd

8.8/10.5

Shots

5/5

 

And this is the same 357 Mag load but with a WSP.

 

As far as putting that much work into a Cowboy load, I do question my motives at times. Shooting a 18" square target at spitting distance doesn't require very precise ammunition. However, it is somewhat satisfying when my ammo does shoot with a single digit Sd. I don't take it to the extremes though, I don't often clean primer pockets and I just drop my charges straight out of my Accumeasure into the case, I do not weigh each charge, not even for testing. I'm no Ken Waters. On the other hand, I do prime each case on my RCBS Lachmiller bench priming tool. 

 

BB 

 

 

 

 

 

["Big Boston"]

12 hours ago, Assassin said:

What was the temperature when you did your testing? And, was the ammo in the sun or shade?

On the day I did the Trail Boss testing I believe the ambient was between 23 and 28 º C.

 

The weather and test procedure were such that sun/shade was not a factor.

 

I'm not overly scientific, however, I do try and limit the variables. Conditions were relatively stable and the test session lasted app 3 hours.

 

452AA was known to increase in pressure when cold, I think TB is fairly stable.

 

BB

[Snakebite]

8 hours ago, Badlands Bob #61228 said:

I think the most important thing is to find a bullet type and OAL that feeds well in the rifle.  Don't over think this.  It's not that hard.  

Badlands is right, don't over think this. Loading for this game is not very critical. There are so many powders out there that will work that I can't even count them all. There is absolutely no need to work up a tight tolerance match load for this game. 

 

Snakebite

[Cheyenne Ranger, 48747L]

learned a new word:  brisance

["Big Boston"]

That's 

2 hours ago, Snakebite said:

Badlands is right, don't over think this. Loading for this game is not very critical. There are so many powders out there that will work that I can't even count them all. There is absolutely no need to work up a tight tolerance match load for this game. 

 

Snakebite

 

That's quite a compliment, thanks. I never considered that my ammo was even approaching "tight tolerance match" quality. 

 

I was anticipating that some of the forum members would be posting chronograph data from their working loads, for comparison.

 

What is the performance standard for cowboy ammunition? When is a load considered bad? 

 

How close do powder forward/rearward velocities have to be to be considered good? Is a 50 fps spread OK? Would 100 fps still be good enough?

 

I did chronograph a factory load, forward/ rearward velocity varied 40 fps and standard deviation was 15 fps. I'd like to think that my ammunition would be at least as good as the factory stuff.

 

BB

 

 

 

 

[The Rainmaker, SASS #11631]

6 minutes ago, "Big Boston" said:

What is the performance standard for cowboy ammunition? When is a load considered bad? 

Bang= good   No bang= bad    BOOM= very bad

I have no idea on chronograph numbers; don't care.

They fit in the guns, they go bang (not boom) and they make a clang (well, most of the time)

What else could ya want?

"When you have to shoot, shoot; don't talk" Tuco Benedicto Pacifico Juan Maria Ramirez

[J-BAR #18287]

I enjoy reading about a well planned and well executed experiment.  Your efforts allow you to KNOW, rather than assume or guess.  There is much reassurance in knowing how much or how little each loading variable contributes to cartridge performance.

 

 I tip my Stetson to you, sir!

[The Original Lumpy Gritz]

Now try small rifle primers in that pistol case. 

OLG

 

[Snakebite]

14 minutes ago, "Big Boston" said:

That's 

 

That's quite a compliment, thanks. I never considered that my ammo was even approaching "tight tolerance match" quality. 

 

I was anticipating that some of the forum members would be posting chronograph data from their working loads, for comparison.

 

What is the performance standard for cowboy ammunition? When is a load considered bad? 

 

How close do powder forward/rearward velocities have to be to be considered good? Is a 50 fps spread OK? Would 100 fps still be good enough?

 

I did chronograph a factory load, forward/ rearward velocity varied 40 fps and standard deviation was 15 fps. I'd like to think that my ammunition would be at least as good as the factory stuff.

 

BB

 

 

 

 

Some folks enjoy reloading and developing various loads about as much as they do shooting them. I was that way for many years. Started loading in the early 1960s, and strived for the same hole on my targets. There isn't anything bad about having a load that is fine tuned for the gun it is used in. As for this game, the targets are generally very close, and large enough that if the bullet clears the barrel, it will usually hit the target, if the gun has been pointed in that direction. 3 gn of ANY fast powder in a 38 spcl using any bullet will work in this game. Some will be dirtier than others, and might require a tighter crimp to avoid unburnt powder. If you enjoy load development, that is great. It will pay off when you run into the occasional small bonus target that is placed at the end of the bay. There is no need to put in anything to hold the powder to the back of the case. Some powders, like Tite Group are pretty unsensitive to powder location in the case. Just use good safe loading practice, don't double charge and you will be OK. Some folks like to use a High volume powder like Trail Boss to prevent a double charge. IMO, it is not necessary.