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outdoorfan
07-12-2013, 09:12 PM
I'm in the late stages of load development for the Rossi 92 .357, and I figured I'd try a few different primers in comparison to the Rem 5 1/2's the I've been using.

Win SPP's were 110 fps slower and were flattened (the Rem 5 1/2's were nicely rounded).

Win SRP's were 135 fps slower.

Rem 7 1/2's were 65 fps slower.

All this with a strong charge of Lil gun and a 190 grain boolit.

I know different primers give different results, but this was WAY out of line for what I expected.

Anyone with similar experiences?

unique
07-12-2013, 10:34 PM
I guess the first question is, how many shots per primer do those number represent?

outdoorfan
07-13-2013, 02:05 AM
5-shot group for each primer.

303Guy
07-13-2013, 02:28 AM
There's a primer power comparison out there somewhere as well as photo's of different primer flashes. It's interesting that the rifle primer yielded lowest velocity. Could that be due to boolit the dislodging? If a boolit gets dislodged then stops against the forcing cone or lead it might end up slower with higher initial chamber pressure. It would be interesting to compare your results with that comparison table.

303Guy
07-13-2013, 02:40 AM
Here's a study I just found; http://riflemansjournal.blogspot.co.nz/2009/06/primers-small-rifle-primer-study.html

Here are the pics of the small rifle primers.

7602976030760317603276033

That last one looks like it doesn't need any powder!

76034

303Guy
07-13-2013, 03:22 AM
Here's an excerpt from another article;


It was a classic case of high gas volume but too little temperature. The primer’s extra gas unseated the bullet while still trying to light off the main charge, producing one peak. Then the bullet retarded as it engaged the rifling, creating the second peak.

Read more: http://www.shootingtimes.com/2011/01/04/ammunition_st_mamotaip_200909/#ixzz2YuKFHDUF

outdoorfan
07-13-2013, 03:23 AM
I have no idea what the issue is. I've never seen this much variation with the bottleneck cartridges I've tested.

ku4hx
07-13-2013, 04:48 AM
Yep, pretty much same for me. I noticed this years ago and for me it validated the loading manual's admonition to re-work up a load if you change components. Larger than usual variations are the major reason I picked one primer brand and for decades used it exclusively. Only in the last very few years have I use other brand primers and that was from necessity; not choice.

44man
07-13-2013, 09:11 AM
Heat without pressure, why I use Fed 150 primers in the .44.
When working loads you look for accuracy first. Changes in velocity should be no concern however you should see different accuracy when you change primers.
303 has found some interesting things there.

outdoorfan
07-13-2013, 10:21 AM
Marshall Stanton at BTB has a pet load of 16 grains H110 behind his 185 gr boolit that he says shoots 1800+ fps out of his 20 inch Rossi using Winchester SPP's. For me H110 has been considerably slower in velocity than Lilgun and then add in the much slower velocity I got from those same Winchester SPP's, and I have no idea why he and I can be so far apart in our experience using these components?

And, once again, I have not seen variation like this in the bottleneck cartridges I've loaded for.

I have some Fed 200's laying around. Makes me wanna try a few of them too.

The non Remmy 5 1/2 groups that I shot hit between 7-12 inches lower on the target at 200 yards. Seems to me that a consistent velocity is important, or a feller should just stick with one primer, like was above said.

I'll probably leave save those Remmy 5 1/2's for the heavy loads and use whatever for the plinking stuff.

Shiloh
07-13-2013, 10:26 AM
I've had minor variation. Nothing I was to concerned with. I don't load, and rarely approach max loads.

Shiloh

outdoorfan
07-13-2013, 10:56 AM
Right, I rarely max out loads anymore either. but this time it was more accurate.

fecmech
07-13-2013, 12:48 PM
I noticed that the WW SP primers gave considerably less velocity in the .357 mag using Blue Dot. The following were all shot in a GP 100 with 358429 and 10 grs of BD. All were 10 shot strings. The WW SP load was 1183 FPS, the Rem 5 1/2 load was 1250 fps, CCI SP mag was 1275 fps and Fed SP was 1254 fps. The ES's and SD's were not great on any of the loads except the Fed SP which was ES-56 and SD-16. The others all had SD's of 20 or better.

outdoorfan
07-13-2013, 04:31 PM
Thanks for sharing. I have a "plinking" load with the same gun using Unique. I will redo the test with that load and see if the result differ any. Maybe this is somewhat of a powder sensitive issue.

outdoorfan
07-13-2013, 04:33 PM
I sure don't want to be swappin primers with the hunting load hoping I still hit the target. LOL!