Teach Me...I Don't Understand

[Southern Shooter]

I have been loading my Ruger SRH Alaskan .454 Casull with 360 gr cast boolits over 22 gr of W296 with Standard Small Rifle Primers. Velocities from this short-barrel revolver have been about + or - 950 FPS.

Today, I loaded the exact same round with the exact same steps with the exception of the primer. I used Magnum Small Rifle Primers.

Velocity dropped to an average of 872 FPS. But, the group tightened up. Why??

Thanks
92415
92416

[Buck-N-Rut]

Not sure why the velocity dropped but you may have gotten a more consistent powder burn which led to better groups. I'm fairly new to this as well.

[dtknowles]

Different day, different results. That does seem strange How many groups did you shoot with the new load? Were the ambient conditions different for the more recent test or did you do a same day two different loads test? Were the primers from the same manufacturer? What was the standard deviation for the velocities of each of the loads tested? How much did the groups tighten up? How long was the time between shooting the old loads and the new ones, what was the bullet alloy and temper, could the bullets have changed hardness due to ageing?

Tim

[Southern Shooter]

The air temp was lower. By about 30 degrees. I kept the gun and the loads warm until at the very moment of shooting trying to off-set that.

[lwknight]

Depending on the brand of primer, generally magnum primers are simply harder to withstand higher pressures. Some brands actually do have higher brissiance

The magnum primer could have given you a smoother light off or a harder start but burned the powder before the bullet exited the barrel lowering the velocity.
Many possibilities available. A harder start and smooth ride should improve accuracy.
Who knows? Strange things happen.

[felix]

Less velocity means less recoil throughout the projectile travel. Less recoil means better pissola control. Primer has to be hit hard, minimizing hammer rebound, to be consistent as well. Those are the factors that must be taken into account for this thread. ... felix

[Southern Shooter]

I can say this...the recoil was not as "shocking" to my hand as in the case of the standard primers.

[mac60]

Come on Felix - pissola - what the hell is that?

[felix]

Revolter! ... felix

[wv109323]

I read an older book by George Nonte about reloading. He claimed by varying the primer and bullet manufacturer that pressures could vary 40%. This example was a 30-06,using the same powder,same brass,same gun and all 150 gn. bullets.
I have heard that some of the more competitive rifle shooters will tilt the rifle barrel upward before a shot so that the powder is in the same position within the case when ignition starts.(?)

[felix]

You heard right! It is far better to follow BR (bench rest) practices whenever possible. That means a full case of powder to eliminate powder position effects. Primer, powder, projectile must be mated to the gun on-hand such that the gun CAN behave identically on a per round basis. In the game of pure BR practice, the condom (copper coated lead) speed is regulated to circa 3300 fps (max) which has been found (over the last 50 years) to provide for the best winning groups. ... felix

[Southern Shooter]

Tried, again. I loaded up 6 more of the exact same recipe, today. Just wanted to see if anything would be different, today.
High- 859 FPS
Low- 796 FPS
Ave- 832 FPS
Velocity still lower than I would have expected.
92663

[lwknight]

Now move your rear site to the left.
Either that or swap sides with the chaw.

[dverna]

Unless there is a dramatic reduction in groups size (and sometimes even if there is) one group does not tell much of a story.

Don Verna

[Dark Helmet]

The hotter primer may be pushing the boolit further out of the case, creating a larger space behind the boolit, thereby reducing pressure and velocity.

[Southern Shooter]

Sooooooooo...compared to Standard Small Rifle Primers, the Magnum Small Rifle Primers are both hotter AND have a harder cup??

[waco]

revolter! ... Felix

lol!!!!

[44man]

The hotter primer may be pushing the boolit further out of the case, creating a larger space behind the boolit, thereby reducing pressure and velocity.
That is usually what happens. All brands are different and some are not "hotter" but some have more pressure and can move out the boolit before ignition. It is the same as reducing the charge.
The .454 gave us fits with starting loads of 296 when the primers moved boolits over an inch down the bore with all the powder behind it with no ignition. Going to max loads only and all fired.
We went to .460 brass cut down and switched to LP mag primers to cure it and got groups down to 1/2" to an inch at 50 yards.
It seems the LP mag primer has more fire without the high pressure jet.
The opposite happens in the .44 mag with groups running three times larger with a mag primer because of boolit movement. The .454 brass is large enough for the LP mag primer and is more accurate with them.

[Southern Shooter]

Well, this past weekend I loaded up some more rounds. The only difference was I upped the charge from 22 grains to 23 grains of W296. Average velocity was 1028 FPS. I have no comment to make other than there was a big difference from the other reports.

44man, I guess filling up the case a bit more made the difference with the magnum primer? I made every attempt to do everything else the same.

[sirgknight]

Less velocity means less recoil throughout the projectile travel. Less recoil means better pissola control. Primer has to be hit hard, minimizing hammer rebound, to be consistent as well. Those are the factors that must be taken into account for this thread. ... felix

pissola...aka pistola....aka pistol. I thought everybody knew that. lol

[Certaindeaf]

All I can say is I never laughed so hard for some time. I don't know why.

[mdi]

Just a thought and mebbe doen't pertain to your problem (?). Reloading consists of a ton and a half of variables. We add a variable here and there and expect the same results (or close to the same), and question why it don't happen. I often get kinda tired of hearing it, but it's true; "every gun is different and likes different loads". The same goes for most components we use, a different lot of powder, a different brand/style of primers, a different crimp, or even a different lube on our bullets can and very often do produce different results.

If it were me, I'd load up a few of each primer type, and shoot them side by side on a few different occasions and record the results. Mebbe the first time was a fluke?

Pissola; a south of the border term for a pistol, after a bit of tequila...

[44man]

Well, this past weekend I loaded up some more rounds. The only difference was I upped the charge from 22 grains to 23 grains of W296. Average velocity was 1028 FPS. I have no comment to make other than there was a big difference from the other reports.

44man, I guess filling up the case a bit more made the difference with the magnum primer? I made every attempt to do everything else the same.
You are on the edge of a failure to fire with 22 gr using the SR primers---ANY SR primer. 21 is the starting load. It means you are getting airspace changes with the low load. Just take it to max of 24 gr. Your low velocities are from the short barrel. 24 gr should be 1447 fps in a longer barrel.
That short Alaskan is competing with a BP .45 Colt.
No, you will not gain much velocity from 24 gr but you will insure the powder lights better even though a lot will burn out front.

[Southern Shooter]

Yes, I will not get any screaming velocities from the Alaskan. Guess that is why I want to keep the boolit weight heavy. At least have some momentum on my side.

Ok. I will leave the Magnum SR primer in the formula and go ahead to 24 grains of W296. Hopefully, will have something to report by the weekend.

Thanks