enlarging the flash hole on a 45-70

[craveman85]

has anyone on here enlarged their flash holes? how big do you go? is it worth it? could it result in powder blowback from the primer pocket?

[e15cap]

I think that made the rounds a few years ago and was found to be counter productive.

[craveman85]

there was some book that someone was talking about and said that it increased their accuracy but i couldnt remember what the book was or if there were any specs.

[cajun shooter]

For the most part the brass, powder, and ammunition people have $1000's of dollars tied up in equipment and research personal. Don't you think that if that helped that someone would have done it and written rave reviews about it. All I have ever seen on the subject is don't do it as it will change the pressure curve and could cause destruction of the rifle and injury to the shooter. Although I do have this $225 CED that might prove them wrong. "Meant as sarcasm"

[Doc Highwall]

Their is two books about enlarging flash holes to .096", one is Loading Cartridges For The Original .45-70 Springfield Rifle And Carbine by J.S. and Pat Wolf and the other is Speer Reloading Manual #14 starting on page 169 which makes for a good discussion or debate.

[craveman85]

well the newer cases probably have smaller flash holes designed for smokeless rounds which will build up more pressure. they dont want to put a bigger flashhole in because some retard would throw a max charge of smokeless in there and blow through their primer. seems like a bp load at about half the cup rating would be fine and maybe benefit from more consistent burning than a smaller flashhole.

[August]

Gradual ignition seems to be the huckleberry for accuracy in the 45-70.

So, softer primers and small flash hole yield more consistent results. That's what my work has shown and what others have recommended.

[Larry Gibson]

Their is two books about enlarging flash holes to .096", one is Loading Cartridges For The Original .45-70 Springfield Rifle And Carbine by J.S. and Pat Wolf and the other is Speer Reloading Manual #14 starting on page 169 which makes for a good discussion or debate.

Doc is correct, as usual. Enlarging the flash hole to .096" is productive with heavily compressed powder charges such as those developed by Spence Wolf to replicate the original service 45-70 loads. It seems of little value with lessor compressed loads. I can discern no difference in psi, velocity or accuracy with my duplex or little compressed BP loads. However, the ES and SD are smaller with the heavily compressed loads using 70 gr of GOEX Cartridge, FFG and FFFG with the Lee 405HB and the Rapine 460500 gr bullets. Any benifit to accuracy was not discernable out to 300 yards though. I do use the .096: drilled flasholes for all my 45-70 BP and smokeless loadings though.....just in case there is a benifit farther down range;-)

Larry Gibson

[craveman85]

ill be using heavily compressed 72 grain 3f loads. i got the extra 2 grains because my rifle has a longer throat and i can seat it out a little farther.

[herbert buckland]

My advice is dont do it (I have tryed it and it defintly destroys acuracy)In Wolfs book were he segests it I belive it was a mistake he forgot to edit as a chapter later he describes how to fix the problem by yousing primer wads.My results over the years agree with August,this advice was also given by the Victorian era shooter who got it right over 100 years ago

[Grapeshot]

If this is the case, then why does federal offer their .45 Auto Non Toxic cases with enlarged flash holes. They also use a small pistol primer as well. But then Federal is using Smokeless Powders which give higher pressures than a case charged with BP.

[NickSS]

Wolfs book suggests the larger flash hole for heavy compressed loads. I tried it and got some good results. However, more recent research has gone the other way. Leaving the primer holes the same as they come from the factory, using wads over the primers and large pistol primers in instead of LRP. I have tried all of these with varying results. I managed to get good accurate loads with all of them and also some poor results as well. I have also had people tell me that they get better results with one powder over another. This is also both true and false. I have come to believe that you can get good accuracy with just about any combination of powder, primers, wads, bullets and flash hole size with a little work. Some powders like Swiss will give you more velocity and less fouling than some others. I personally no longer can shoot as well as I used to so most everything I have will only shoot 1.5 to 2 MOA. No matter what I do for loads. I have a young friend who has great eyes and is in great condition. He shoots BPCR and his loads crafted with all the latest ideas for accuracy. Typically I have seen him shoot 4.5 to 6 inch groups at 600 yards almost every time we hit the range together. When I shoot his rifle with his ammo, I get groups that go 6 to 8 inches at 600 yards. That is the difference in ability of the shooter.

[Doc Highwall]

NickSS, that proves that their is more then one way to skin a cat. Some times we forget that we have to listen to what the rifle is trying to tell us.

[Lead pot]

I suspect that there is a lot of brass in the scrap brass box from flash holes that were enlarged including the box I have.

If you want to improve consistency you might want to get a set of number drills and find the largest average hole, not the largest hole and make all the holes the same and remove the burs on the inside of the case that gets pushed in when they punch the flash hole in the primer pocket and find the mildest primer no matter how much compression you use. Try several different types of primers. You will be surprised the difference primers make.
One thing that is a big destroyer of accuracy is a inconsistency of case necks, well you say I finger seat my bullets. Even if you finger seat the bullets before that bullet leaves the case mouth using black powder it gets expanded and the case neck walls will have different tensions on the bullet.

You just might like the results on the down range target.

Kurt

[Doc Highwall]

Here is a tool I made to ream flash holes to .096". I took a # 41 bushing and ground down the end to just fit in the primer pocket hole too make sure it would center the hole and then I bored a scrap piece of aluminum to help keep it squared with the case head. I have only shot these cases with smokeless AA5744so far.I plan on using them with black powder and a piece of paper over the flash hole next year. I have a lot of Irons in the fire now and I am working on modifying dies for my 308 Win and hope some of the ideas will be able to be used with my 45-90.

[Kenny Wasserburger]

Rule 3.17 of the NRA Rule Book.

Smokeless up to 20% of the Charge maybe used in NRA Long Range-Target Rifle Matches.

However: The National Championships at Raton NM Require 100% Black Powder Loadings.

Leadpot is right neck tension is a real accuracy killer.

I use a lyman uniformer for the flash holes, and debur the inside of the flash hole at the same time.


I anneal my case necks after every Firing.

The Record speaks pretty clearly on how it works for me.


The Lunger
Kenny Wasserburger

[northmn]

Mathew in his books recommended enlarged flash holes for BP loads. In another context he recommended that the processs may have had benefit in making them uniform. He definitely recommended the reaming process to eliminate the burring. I had good results with magnum primers using GOEX, but some claim Swiss likes a soft ignition, to the point of pistol primers. I saw no gain in enlarged holes and have heard that they are dangerous for smokeless. Do not know if I care to have cases laying around for that reason.

Northmn

[Dframe]

I've never intentionally enlarged flash holes. I've only used a uniformer on occasion when I found one too small.

[KCSO]

The flash holes in the old FA cases was about 096 and they also used the hotter mecuric primers. When I started shooting B/P cartridges I used old military case so when I switched to modern cases i reamed the flash hole and used magnum primers. It seemed to help with fouling a little but accuracy wasn't any better so I quit reaming the flash holes. Unless there was some pressing reason to try and duplicate military ammo I wouldn't bother.

[dromia]

When I got my first trapdoor I went the Spence Wolf route and found it to be very effective on the target. Haven't deviated from Spences recommedations as I've never needed to.

[herbert buckland]

I enlarged the holes on some 56-50 spencer rounds,from the start acuracy was bad and it got worse the more I yoused these casses,I tryed to save them by puting a primer wad under the pouder,this inproved acuracy but not to the point of the untouched casses,this has been my experince with one caliber and certently not proof one way or the other on other cartriges,but for me it was a good way to turn good brass into scrap

[RMulhern]

Useless as tits on a boar hog!!