Opened up flash holes..a test

[Char-Gar]

When I shot the Springfield NRA Sporter yesterday, I took the oppertunity to shoot the rifle with cases which had the flash hole opened with a 28 drill and the same cases that had not been modified.

I could see zero difference between the size of the groups, point of impact or appearance of the fired primers.

The load was LC 67 Match cases/311284/18/Alliant 2400/ Rem. 9.5 primers.

[LAH]

I've never took time to open flash holes. I read it done and how well it works but never tried it. Don't guess I will. HEE HEE

I really like 2400 in my '06...........Creeker

[Phil]

I don't think it would make much difference with the loads we use in cast bullet shooting but I wouldn't want an oversize flash hole to shoot max charges with jacketed bullets.

I have read something on this years ago but can't for the life of me remember where or what the results were. Dang it, this getting older stuff ain't all its cracked up to be.

Cheers,

Phil

:-D

[Char-Gar]

Creeker... I really was hoping for the results I obtained.. i.e. no difference. The notion behind this all if to prevent bottle neck 30-06 cases from shortening with the use of light loads.

[Phil]

Thats what I read! Think it was in an old Rifleman, back when they had useful data in them! I recall they said to be sure to segregate the cases with drilled flash holes to make sure they weren't used with full loads. Hmmmmmmmmm.........I may do that with some cases I use for round balls and Bullseye to shoot indoors.

Cheers,

Phil

[Harry O]

I have read about opening up the flash holes for black powder cartridges. It is supposed to be better than using magnum primers to ignite the powder. I have been meaning to try it, but have not gotten around to it yet.

[9.3X62AL]

Not wanting the topic to stray far and wide......but Harry's text prompts a question for me. What is it about black powder cartridges that requires (or maybe recommends) the use of magnum priming or flash hole expanding? From all that is written and known about The Holy Black, it is a lot easier to ignite than the smokeless fuels. I think we need look no further than a flintlock rifle for a real world example of that. I don't see a panful of Bullseye being able to set off a chamber full of IMR 4350 with any sort of reliability, pressure considerations of both the platform and the fuel's behavior aside. Empirical evidence would tell me that the smokeless powders would need the hotter spark provided by magnum priming more so than THB--but most smokeless loads do their best work with standard priming.

I look forward to some of the BPCR folks adding to our knowledge base here

[Jon K]

Not wanting the topic to stray far and wide......but Harry's text prompts a question for me. What is it about black powder cartridges that requires (or maybe recommends) the use of magnum priming or flash hole expanding? From all that is written and known about The Holy Black, it is a lot easier to ignite than the smokeless fuels. I think we need look no further than a flintlock rifle for a real world example of that. I don't see a panful of Bullseye being able to set off a chamber full of IMR 4350 with any sort of reliability, pressure considerations of both the platform and the fuel's behavior aside. Empirical evidence would tell me that the smokeless powders would need the hotter spark provided by magnum priming more so than THB--but most smokeless loads do their best work with standard priming.

I look forward to some of the BPCR folks adding to our knowledge base here

I have never taken the time to open the primer flash hole- more work than I want to do, BUT here is what I have found when it comes to magnum primers and BP and Smokless.

BP:
Powder compression, I think is one of the biggest factors for needing the mag primer. I also think that is why manufacturers are making pellets with a hole in the center- for better ignition.
Not all BP shooters use mag primers, some use standard & some like pistol primers. for what limited testing and shooting of BP I've done, the chronograph and group tests show me more consistant and smaller groups w/mag primers(regular Goex .125-.450 compression). Each gun may like something or a brand of primer better than another.

Smokeless:

I've tested primers in most case sizes, and have not seen measureable difference in medium and small cases, but have seen where the large magnum rifle and belted cases won't shoot without the magnum primer. Although brand to brand(primers) in a given application will show exactly what a gun likes.

That is just my $.02 worth. I am not trying to or looking for debate, and none of what I have to say is hear-say I have it all backed up on paper, so just take it at face value. Again Only an Opinion!

Jon

[floodgate]

Al:

To the contrary, in the last several issues of "Single Shot Exchange", BP guru Paul Matthews has been promoting REDUCED flashhole diameters for the larger black powder cartridges, and Kermitool, Inc. <www.kermitool.com> is making swaging die sets to "reduce and uniform primer pockets [flashholes] from 0.080 to 0.062...helps provide more uniform ignition from shot to shot."

Hmmmm....

floodgate

[John Boy]

What is it about black powder cartridges that requires (or maybe recommends) the use of magnum priming or flash hole expanding?

Al, maybe this will explain why:

Black powder grains are sulfur and potassium nitrate impregnated into charcoal that goes through the following processes that are polished with graphite which produces irregular shaped grains by sporting grade:
- Wheel Mill
- Mill Cake
- Roller Press or Plate Press
- Corning
- Screening
- Grain Sizing
- Powder Polishing
- Drying
- Packaging

When charged into a cartridge case, the loose powder is compressed to a cake to ‘eliminate’ the air space between the grains and not crush the grain sizes. Loose powder generates irregular ignition. BPCR compression is recommended to be in the range of 0.15 to 0.5" and is dependent on multiple variables of the reload

The ignition pressure curve for BP is a high spike curve v white powder being a sloped pressure curve. The ignition gases approximate 3000* F

When the compressed powder charge in the case is ignited by the primer, the objective is to ignite the graphite glazed irregular – non uniform grain sizes as quickly as possible and uniformly through it's pressure curve so the velocity SD’s are less then 10.

Accordingly, the more power (brisance) the primer has, the better the SD objective can be obtained by burning off the graphite on each grain, igniting the irregular shaped multi-sized grains of the compressed cake (that has no air between the grains to aid ignition) to reach the proper ignition curve.

Brisance: Is the shattering or crushing effect of the sudden release of power in an explosion

The primer holes are opened up to aid the primer power to ignite the compressed powder more quickly. Some folks put a newspaper wad over the primer hole to more evenly distribute the brisance during the explosion

Examples of primer power popularly used by Black Powder Cartridge Rifle shooters for bullets 400grs and heavier (long distance shooting) are:
Federal 215M … brisance 5.69
CCI Br2 … brisance 4.37
Others are used too, depending on the charge and bullet weight
And don’t bet that you can get 10 BPCR shooters agree that one primer is the best/better

Examples of the Grain Sizes
Goex FFg, regular production grain sizes.
20 mesh - 79.2% retained … 0.020mm
30 mesh - 20.8% retained … 0.030mm

Goex FFFg, regular production grain sizes.
20 mesh - trace retained … 0.020mm
30 mesh - 70.8% retained … 0.030mm
40 mesh - 26.2% retained … 0.040..
Thru - 3.0% …… smaller than 0.040mm

Hope this snippet helps explain why hot primers are used and primer holes are opened. Please remember also, there are many opinions what is the 'best way' ....

[9.3X62AL]

Many thanks for the texts above--that all stands to reason, for sure.

This place is great.

[Larry Gibson]

Creeker... I really was hoping for the results I obtained.. i.e. no difference. The notion behind this all if to prevent bottle neck 30-06 cases from shortening with the use of light loads.

Charger

Your test was invalid; reason being your load of 18 gr 2400 under the 311284 was a normal cast bullet load. Pressures are high enough that the shoulder is most often not set back. A "light" load would be something on the order of 2-3 gr Bullseye under a lubed .310 RB or a 80-90 gr cast bullet. Shoulders will setback with only a few such "light" loads unless the flash holes are reamed. Cases fired in rifles with controlled feed extractors will have their shoulders set back only as much as the ectractor will allow the case to move forward. Misfires may or may not occur after several firings with such light loads (in cases with unreamed flash holes) depending on how much setback the extractor allows and on the firing pin protrusion. Many push feed rifles are prone to misfire and fail to extract after a few firings per case with such loads. Minimal tapered cases are prone to greater set back with less firings.

Try taking one case (unreamed) and fire 3 gr Bulleye under a 90 gr bullet, the Hornady swaged SWCs or WCs work well if you don't have a mould. After 2-3 firings I'll bet you see the shoulder is set back as the primer prtrudes farther with each firing.

Larry Gibson

[Char-Gar]

Larry....Tests are valid or invalid depending on what you are trying to test.

I was trying to see what effect opened flash holes had on 18/2400/311284. The answer was "none".

My question is whether or not cases with enlarged flash holes, can be used for the entire spectrum of cast bullet loads, from the ultra light, low pressure gallery loads to the regular pressure cast bullets loads.

Thus far, it would see that you can.. emphasis on "thus far".

I want a lot of cases, fire formed to the chamber with full snort condom loads, that can be neck sized and used for all cast bullet loads.

[Larry Gibson]

Charger

I was responding to; "Creeker... I really was hoping for the results I obtained.. i.e. no difference. The notion behind this all if to prevent bottle neck 30-06 cases from shortening with the use of light loads." It was in that respect I referred to your test as "invalid". I have been experimenting with the cases having flash holes reamed for all of my regular cast bullet loads with rimless bottleneck cartridges. So far my tests have shown a consistant improvement in extreme spread and standard deviation even with loads like a 311299 over 4895 at 2000 fps in the '06. There is a noticeable improvement also in more uniform ignition with light loads of faster burning powders. Whether it justifies the effort to those who only shoot at 50 or 100 yards is up to the individual. I like to shoot at 200 to as far away as practical so uniform ignition which translates to accuracy is important to me.

Larry Gibson

[Char-Gar]

Larry... That is a good piece of information. Thanks..

[Harry O]

Not wanting the topic to stray far and wide......but Harry's text prompts a question for me. What is it about black powder cartridges that requires (or maybe recommends) the use of magnum priming or flash hole expanding?................I look forward to some of the BPCR folks adding to our knowledge base here

I don't know the answer you your questions. I have read a lot about BP loading and have come to the conclusion that there is more voodo and black magic surrounding that past-time than there is with bullet casting. There are a number of books, magazines, and articles about it. And everyone seems to have a different opinion. From what I have read, though, more people seem to recommend Magnum primers (at least on cartridges larger than 32-40 or 38-55) than not. There is also a minority that believe opening up the primer pocket hole will substitute for the Magnum primer (ie: you can use a standard primer with a large hole).

The major problem with opening up the primer hole is that powder (particularly compressed BP) can become wedged in the hole and make the ignition less uniform. Some have suggested (including Steve Garbe at one time) putting a thin layer of newspaper right over the primer pocket and before the powder is placed in the case. That kind of stuff is too much bother for me. Any more, Garbe seems to be death on compressing powder and using Magnum primers, but his opinion has changed before and will probably change again before we die.

I did some testing on my 41 Long Colt when I was wringing that one out. I am staying with Magnum primers for that one even though the case is small. I have read that it does not help in other small cases, though, and can actually hurt. Until I do some testing by myself, I don't know where the truth lies. Most likely, the truth lies in several places with directly opposite solutions -- but ones that work for the individual who worked them out for him, his loading, and his gun.

[catboat]

I uniform my flash holes with a K&M tool. Works great, and it's a good design. The collar serves as the depth stop and comes in contact with the interior case head-not the case mouth (like the lyman). The procedure uniforms the "roundness" of the group. I would say that groups are reduced about 20% by doing this step.

[hydraulic]

Spence Wolfe, in his book on trapdoors, broke up several old Frankford Arsenal .45-70 cartridges and found the flash holes measured 1/10 of an inch, larger than modern .45-70 cases. His conclusion was that the larger flash hole was necessary when loading black powder. Our guys, (1st U. S. Infantry of Fort Randall, SD.), are careful not to load any of our drilled out cases with smokeless, though we see little reason to own any rifle other than a trapdoor.

[Willbird]

The old gun writers to a man insisted that the then "new" hotter smokeless primers were not as accurate with black powder scheutzen type loads, and those guys sure would know the differance :-). They hoarded the old "soft" blackpowder primers.



Bill