I’m sure you old hands have kind kicked this around a hundred times, but I’m new to this so I’ll ask.
Have any of you done actual testing to determine what primers give the lowest SD?
Specifically I’m interested in the results with straight wall cases and heavy, long range loads.
JKR

In this regard I'm of the firm belief that a rifles choice in primers is the only thing exactly like smokeless. Some rifles like this primer some don't, once in a great while a rifle just isn't picky. Some lots of powder resond well to primer A the next lot might be absolutely repulsed by that primer.
I will say that across the board I generally start initial load work up with either the RP 91/2 or BR2 and then when tweaking loads wander off into the primer box.

jim,
Federal 150/150M LP primers if you can get them.
Arnie

I have a high curiosity :S I like spending time on the range or here at home on my 130 yd range.
I have tested the effect of primers mostly for the .44-77 and the .44-90 BN and I used several different brands with 10 shot groups using the same powder loads.
CCI 200 LR, Br2, Win pistol and LR Rem lr and pistol, Wolf LR, Lellier&Bellot LR, Fed 150 Gm Fed 210GM as well as Fed 215 Mag.
All in all I give the Fed 150 GM a slight edge over the Fed 200GM. The Wolf is 3rd for tightest groups.
Just lately since I got my new .38-50 Hep I been using up my old green box of CCI 200 primers that has a price tag of $8.05 per thousand and the yellow box of CCI 200 marked $10.68 and I really should save them for match they put sub MOA at 200 using them.
But my go to are the Fed GM LR and Pistol primers. They are the most consistent down range in all of my rifles from the .38 to the .50

Interesting.

Don,
Is your answer based on actual shots fired over a chronograph? Or do you, like me, base your conclusions on groups fired on the target?
This is something that I never gave a great deal of thought to in my former life as a high power shooter. It was Federal 210M’s, a good bullet and the appropriate powder, and good things would happen if you could hold hard! Now I’m told that SD should be between 5 and 10 and the key to this is the right primer.

Arnie,
I’ve heard good things about Federal 150’s. Unfortunately I don’t have any at this time.
I’ve tried other pistol primers in the past but didn’t see any difference. No chronograph tests though.
But what’s the deal with large pistol primers contributing to damage to the face of the breech block?
I just have a hard time wrapping my head around that!

JKR

Jim,

I seldom put up a crony for testing loads I let the hols in the paper tell me what is working.
I used the to see what the .38 was doing for velocity and you can see on my target that even with a high ES and SD the 100 yd group is still tight compared to the other results on the target.
That brass I was using when I ran this test was not fully formed yet that might explain the ES and SD I found with this new rifle.
I might set it up again now that this brass has been fired several times.

Jim I quit choreographing after I figured out group size at distance is where things happen.
I do if going someplace that has velocity requirements chronograph, but heck even the NRA quit that after they go 2 shot out from under neath them at Raton a few years back.

Don,
Since you have the luxury of being able to test at long range, what do you see in terms of accuracy comparison at say 300 yards as compared to 1000? If your long range load will hold 6” at three hundred, will it hold up at 1000?
Here on the East side of the river we only see the results of our long range loading efforts when we go to an actual match. I’m lucky to have 300 yards but many of us can only have one or two hundred.
We do have a few 600 yard paper matches and gong shoots. I feel these are a better test of ammo performance .
Jim

I start my load testing at 600. Sometimes a load that looks good at 6 will be just ok at 8 and 9 becomes dismal and 1000 is just an excerize in emptying cases. I try to do initial tests in relative calm conditions and then when I find something that looks to hold up all the way to 1000, go back and test at 800 and 1000 in less than ideal conditions. What I look for in the less than ideal conditions is the amount of vertical dispertion. Horizontal can be affected by all manner of conditions, but vertical tells the story. I look for something close to 3 moa vertical at 1000. I also look at bullet impact on target, is the bullet leaving a nice point first round mark, or do we get oblong or sometimes even full profile side views.

I wil also say it is a head scratcher to me how a full profile side impact can still fall within acceptable vertical