Rifle Primers

[Deanm1874]

Gents:
Just got done building my “long range” muzzleloader as I call it, perhaps slug gun.... whatever. Don’t know if anyone has ever built one like it... if so never heard of it. I “thunk” it up laying awake in bed some years ago and finally moved on it. Purchased an original 43 Spanish Roller, bad rotted barrel... perfect! Pulled it and chucked it. Green mountain barrels had an internet special on breach plug threaded muzzleloader barrels 1” across the flats. .458”groove 1-18 twist 34” long. $168.00.
I chucked it in my lathe and threaded it for the roller action. Installed a solid breach plug and then drilled and bored it out to groove diameter. Then cut a 1/2” deep “chamber” that would take in a 1/2” 45-70 casing. It serves no purpose other then to hold a primer for ignition. It will extract , allow wiping from breach for fouling control, install a new “primer module” close breach, reload with a paper patched 550 gr slug.
Upon 1st trial.....
I discovered gas leakage from the breach... accuracy was sub MOA... nice!! But problems with gas sealing at the breach. Brass walls back by the case bottom is thick... so I thinned the wall down to .015”. Next test....
Perfect gas seal achieved.... but accuracy went to 2 1/2” MOA. Hmmmmm...
here’s where I got to thinking.
What I am 90% sure what is happening is...
when the primer detonates.... primers of today have A LOT OF POWER ... it blows thro the column and moves the projectile before the powder does... when the powder actually does go to work there no longer is bullet to powder contact.
In my 1st test... I had poor gas seal at the breach....the primer pressures were escaping and not moving the bullet prior to powder pressure was.
What I do know is...
Primers in the 1870,s were no where near the power that we use today. Primers today are meant to ignite smokeless powders which takes a lot more force to ignite than black.
I did some research and yes.... there is a primer demonstration on the 6mmBR forum that shows the fire power of today’s primers on a high speed camera. It is surprising the differences in brands of primers.
According to the photos , a federal SR primer looked to be the “weakest”primer.
I have long been mulling over the idea of our primers today are actually not the best suited for bpcr.... especially for paper patch biz on account of the bullets being seated in by hand pressure , and mine and like many others, are bore riding... nothing much to keep them in place while the primer ignites.

[Lumpy Grits]

I use a piece of white coffee filter paper at the bottom of the case in my BPCR loads.
Had very good luck with CCI br2 primers.

[Deanm1874]

Here is what I am thinking of doing.
Machine my own primer modules and design them for small rifle primers and use the weakest primer I know of (federal small rifle).
For now I am changing to large pistol and hope I don’t pierce it. No biggie if I do for testing purposes but don’t want to use them long term. In all of my jabber here , just was curious as to what others thought of this.
Here is my biggest issue, read an account of Hiram Berdan performing a rifle test with pp ammo. He reported fantastic accuracy. At a 1050 yards a string of 20 rounds shot 2 MOA. I find that incredible accuracy. Gun was never cleaned during that whole test. Beef tallow and beeswax for fouling control. I personally know I’ll never do that currently and know of no one else capable of that either shooting in the same manner as he.
I know I get my best accuracy with large pistol primers... a bit weaker than large rifle... but then they get pierced, firing pin stays stuck in the pierced hole and I can’t lower the breach.
The only main difference I know that he had different was ignition power of primer.
I know this.... when I had gas leaking from my muzzleloader breach I shot VERY accurate....
sealed off... I shot poorly.
Nothing else was different...
The only explanation is , all the force of ignition was kept inside and the bullet moved before the powder did.

[BFD]

Muzzleloading Benchrest slug gunners used modern primers w/o a problem. And I, and many others, use bore diameter bullets just like yours on top of a charge of powder and rifle primer just like you are doing and we don't have any particular problems.

2.5 moa may just be your starting point. That your rifle appeared to shoot better with blow by, you might try smaller charges next time out.

[Deanm1874]

Yup tried smaller charges... no diff in accuracy

[Deanm1874]

I wonder if slug gunners using modern primers have a much smaller flash hole than my set up. Typical flash hole size usually run around 1/16” (.062”). If flash hole is much smaller than it definitely would reduce the volume of energy into the powder charge on ignition

[Deanm1874]

Lumpy grits...
You mentioned you put wadding in front of your primer. I did some testing. I placed .006” paper in front of mine... held a piece of paper against the muzzle and fired it. I found no reduction in force compared to a primer with out wadding in front of it. So I tried .015” wad.... still no reduction... tried .030”.... still no reduction. All the papers held against the muzzle of the 34” barrel had big holes ripped thro them. The primer wads had flash hole sized donut holes in them. Wad.... no wad... damage to the test papers all had equal damage. Wads were in the primer pockets primer seated on top of them.

[Lumpy Grits]

The target said for me to do such.
Really dropped the ES in MV, and that helped to tighten up the groups.
Gary

[bpcr shooter]

Im with lumpy on this as well. I use a BR2 with a legal pad over primer wad. With out it my groups open a lot!!

[Deanm1874]

Cabin tree Mfg has a primer tester. Measures the force. You get to see the power, consistency etc from lot to lot, and brands
thought it was kinda neat.

[BFD]

Cabin tree Mfg has a primer tester. Measures the force. You get to see the power, consistency etc from lot to lot, and brands
thought it was kinda neat.

The data that Cabin Tree published on the primers they tested convinced me to use BR2. Never looked back.

[Coltsmoke]

You are saying the primer going off had pressure that went up thru the powder column and before the powder went off the pressure some how went around the wad, around the base of the bullet that was sitting barely in the case (being a PP bullet) without moving the bullet, then went backwards down the sides of case before the powder went off leaving the bullet in place for the powder charge.

I would say you had some gas blow by when the powder went off. Then you solved the problem. Second test, I think one of these three things happened. You sealed the gas blow by and the velocity changed enough to change the accuracy of that powder charge. I really don't think that would do it. Number two: If you took the .015 off the inside of the case walls the same powder charge would sit lower in the case and the amount of compression on the powder would be less and that changed the accuracy of the load, if the thickness came off the inside of the case. Number three: You experienced what everyone else has at one time or the other, that load shot great the first time I tried it, now it's not worth a crap, what happened? Been there and done that many times as many others on this forum.

I've shot some great 10 shot groups using pistol primers with .007 paper under the primer. No primer problems in my loads.

[Lumpy Grits]

Cabin tree Mfg has a primer tester. Measures the force. You get to see the power, consistency etc from lot to lot, and brands
thought it was kinda neat.

The data that Cabin Tree published on the primers they tested convinced me to use BR2. Never looked back.

Br2 is all I use in any competition rife ammo.
I listen to what the target shows over anything else.
If I couldn't get br2, would go with Fed GMM.
OLG

[opencountry]

I've been placing a piece of standard copy paper under my primers (WLR) after hearing of this maybe five or six years ago here on this forum, and it's something which helped improve my results downrange. I'll continue with this. 45-90, 45-110 PP'ing.

Robert

[Deanm1874]

Coltsmoke.....
I have a ML slug gun. The “casing” I am referring to is only 1/2” long...I took a 45-70 casing and cut most of the side walls off... all I have left is maybe 1/4” long side walls. The casing is now only good for holding a primer, no powder. The gun in essence has no chamber except for the very short stubby casing. When the casing is that short the side walls way down by the flash hole (webbing).... they are thick... to thick to expand and seal off gasses. So I thinned them down to .015”. So now on ignition they do expand and seal off.
As far as primer force moving the bullet before the powder actually has a chance to burn and build pressure and move the bullet, yes I think that is possible. Think about it... primers today are much more forceful, they have to be, they are designed to ignite powders that require that amount of force to detonate. Case in point.... if you have a cap n ball revolver, take some IMR trail boss powder and put a charge in it... take a # 11 muzzle loader cap and see what happens.... if it does manage to ignite on the first try it will likely be a major hang fire.... most times ffor me it took 2 tries (2 caps) to get it to go off and then it had a major hang fire.... pap.... boom! That never happens with BP... unless the powder is damp or nipple clogged etc...
Modern primers are forceful.... they will move a groove sized bullet that has approximately .002” brass neck tension down the barrel a good ways on there own with out powder present at all.
Now.... take a paper patched bore sized bullet that has very little to no neck tension ....and is not initially gripped by rifling, everything is slip fit. A force as strong and sharp as primers put out...yeah I think it a possibility it jars/moves the column of powder/wad/bullet.... the whole bit....before the powder actually does. Hence an air gap.
Now.... I am not seeing any of this. Not possible. The only thing I know is this....
in my muzzleloader slug gun... beings I have very stubby short casings... and before I had thinned what short but very thick side walls there were....some of the force of the primer may have escaped out around the short sidewalls and out by the breach block....enough so that it didn’t move powder/wad /bullet prior to powder pressure build.
So here is going to be an experiment I am going to do.
Machine a adapter that will thread in a revolver nipple, and try #11 caps. They contain way less force then center fire primers.... just see what happens.
It will be a safe experiment... everything is secured by the breach block.
Just have not got around to it as of yet. Gimme couple weeks.