Pressure Trace Test for .041" Tungsten Bushing

[Deleted]

All the testing I did with the .041" x 1 and .029" x 2 bushings really doesn't mean much unless you get the Pressure Traces to prove it.

Check out the velocities and ES from normal fit bullets to drop down the barrel bullets.

The .041" x 1 did better than the .029 x 2 when it comes to ES. I'll post that later.

Remember now these Pressure Traces are comparing normal fit bullets to drop down the barrel fit bullets.

Thank you so much Ralph!

[Deleted]

I can't tell but is that out of a 25" barrel?

[Deleted]

Pretty sure it is.

[madcityhoosier]

not needed now

[Deleted]

madcityhoosier, Thanks for posting the actual picture of the Pressure Trace!

[rangeball]

Interesting. I like where this is headed.

[Jon]

Interesting keep up the good work. Thanks for all your effort.

[rangeball]

Apr 7, 2014 20:53:54 GMT -5 Earnhardt said:

The .041" x 1 did better than the .029 x 2 when it comes to ES. I'll post that later.

Very interested to read more about this. Depending on the difference, x2 may still have advantages to prevent smaller grain size powders from getting into the vent hole.

[Deleted]

Yep .029" would open up some options for sure

[Dave W]

Very impressive! Thanks to E and TG for making this test happen.

[deadeye]

tgin pa-it states 2/3 sl primer bulge-any pics of primer by chance & your assessment of the spent primers. / tia

[Deleted]

Note how the powder still ignited with the drop-in bullet and the .029" x 2 bushing, but the velocity for the drop-in bullet is 60 fps lower.

So even though the .029" x 2 has approx. the same area as a .041" x 1, it doesn't ignite the drop-in bullets as well.

So we're making the holes in the 2 hole bushings bigger.

[Deleted]

Here's another Pressure Trace with the .041" x 1 with H4198 comparing a normal fit bullet vs. a drop-in bullet. ES is fairly tight, but PSI is off.

[Deleted]

I notice these various tests were full form. People having ignition issues with full form and loose fit bullets? Full form / Smooth........totally different IMO.

[TGinPA]

The tracings above were all made sizing with smooth form dies shooting from a 25in .458cal barrel.
Primers i3031 90gr 310APB .041 bushing.

TG

[ET]

That is a nice overall healthy looking trace.
But the slight primer bulging of the 209 still persists even in a larger bore diameter SML.

From some reasoning I believe a primer shelf may be the answer to reduce this bulging affect and maintain level of thermal energy delivery to the powder.
My first impression of primer bulging was pressure entering the primer hole and forcing the side out. But as pressure enters the flame channel it is also pushing against the bottom of the primer trying to escape/equalize. By confining the pressure into the primer only and not having the pressure assist with a push from the bottom bulging should be reduced or eliminated until a higher amount of pressure is introduced into the flame channel.

So the hypothesis goes.


Ed

[Deleted]

So you guys are reducing a .458 310 APB that much to shoot smooth sabotless? Pretty good primer bulge....

[hankinsrfls]

To much pressure getting back to the 209. Wait till one of them rupture and all that gas goes in your face. Won't be a pleasant experience. The primer wall was never meant to hold that kind of pressure.

[Deleted]

Stupid question.... Is the rifle being traced 25" rempac or savage wearing the pac?

[cowhunter]

If a 209 primer ruptured in the lower half, which in the 700ml design is the only area not covered by the breech plug, what would happen? Do you think the blast could get to your head or would it go to the side?

[hankinsrfls]

Cowhunter.. Most of the gas will be dispersed out the side but there will be enough gas to exit the back of the bolt to make you think twice before shooting another round. I say this from experience,, that's why I designed the system I use now.

[edge]

I don't know about the Remington, but the Savage has a gas relief hole on the left side of the action even with the back of the bolt head.

If the 209 ruptures the gas JETS out of that hole and if your arm is there you will regret it!
I did have it happen, but fortunately I don't hold the forearm at the range.
I was using a ballistic bag type rest and it put a nice burn spot in the bag!

edge.

[cowhunter]

Thanks Jeff. I don't mind a little hot blast but I'd like to avoid wearing a patch on one eye. Do SML shooters generally wear safety glasses and would they stop any rupture particles?

[moto357]

When I started shooting a Remington centerfire conversion I made a few years ago I was using Pete's plug. Once the nipple started gas cutting I had a blast to my face every time I pulled the trigger. It wasn't bad and I didn't lose an eye or anything, but I immediately began wearing shooting glasses. I'm sure gas/pressure was going in all directions but there was indeed plenty that went through and out the back of the bolt. With a primer failure being worse than a little gas cutting I have no doubt there would be a more intense blast.

Long story short, just like a mark on my ramrod I also wear eye protection when shooting. Much rather have em and not need em...!!

[Alabama]

I would think safety glasses would be recommended. But not required.

[Deleted]

We have about 100 rounds through the .041" x 1 and the .029" x 2 bushings with no primer blow outs.
With some of the rounds launching a 310 APB at 3000 fps +.
How many of you are truly scared of the primer blowing out every time you pull the trigger.
The odds of there being a primer blow out with this bushing are minimal.

I wonder if the post stating that one should be fearful of gas dispersal from a blowout with this .041" bushing has been trumped up to get people to shy away from using them?

We are not going to stop using these larger holed bushings.
We are actually going larger with the 2 hole bushings if that is any indicator.

Especially now that Precision Bullets has a Savage LRM kit available for the ML II. (I'll post results when I start shooting it)
The other LRM kits out there will be able to use the larger 2-hole bushings as well.

[Deleted]

I wanted TG to do some pressure traces with a very slow burning powder in the .458 to see if a 209 primer and the .041" bushing would ignite H4350 with drop-in bullets with no seating pressure.

ES of 1- between the 2 very loose bullets with zero seating pressure










Between all the loads with the very slow burning H4350, the powder ignition with the 209 primer, very loose bullets with no seating pressure ,and the .041" bushing, is excellent.

TG noted that with the booster there isn't any powder burn outside of the barrel.

[Deleted]

With these tests and cowhunter lighting 4350 with the pr adapters, things are looking promising for the slower powders! Could see a lot more high speed rigs in the future.

[Dave W]

Apr 10, 2014 13:51:04 GMT -5 edge said:

I don't know about the Remington, but the Savage has a gas relief hole on the left side of the action even with the back of the bolt head.

If the 209 ruptures the gas JETS out of that hole and if your arm is there you will regret it!
I did have it happen, but fortunately I don't hold the forearm at the range.
I was using a ballistic bag type rest and it put a nice burn spot in the bag!

edge.

Been there-done that. I do hold the forearm and my arm got scorched when a primer blew in the ML II.

This is not meant to try and persuade people to not experiment, just a warning. Edge knows what he is talking about!

I do not know the tipping point, from point A(bulged primer) to point B(blown primer), but I prefer to stay away from primer bulging loads.

If you really want a thrill, blow one in a Ruger #1, that will really get your attention.

[Deleted]

I wasn't talking about edge.