Gentlemen,
I'm waiting for some primers to be delivered so I thought I'd have some fun and shoot some other kinds I had laying around to see if there is that much difference in the way the rifle shot. Turns out there is indeed quite a differenct.

Granted, I worked up the load with the FGM205M so they should be the most accurate. I'm not saying the others cannot be made to shoot, but from one rifle, with one load, on one day, they were by far the most accurate. See below

Ruger #1 K1V-BBZ 204 Ruger, 32gr Hornady V-Max, 28gr Benchmark, chrony at 4170fps. Temp 29 deg, light to no wind.

The top right is two groups, I shot the first five to confirm the POI and get my control group, then I shot the other three primers and came back to see if the FGM205M was still shooting, I aimed at the right side of the star, had one flier, and then shot the other 3 shot group.

Enjoy,
Jimno

I'll often work a load up using a match primer to start, then try diff. primers to see if group size changes much. Small calibers/rifles seem more sensative to this than the medium or big bores.

Very Good Jimno this a great subject ! Do you know that brass with of center flash hole will do the same eratic bullet spacing ? and the flash hole is critical as to the size of hole ?

concho,
I hear ya. Since the only brass I have is from factory loaded Hornady I shoot them and then reload. I did notice about 8 of the 20 in one box were off center. They were tossed. I also deburr all the flash holes and am quite surprised at the burrs I find. I've not yet uniformed the hole, but there is always tomorrow.

Jimno

I've moved to BR primers. They should more consistent for only a little higher cost. After work-up, I don't expect it to show much change in group size over standard primers, but I do expect to lose those one-in-twenty-groups fliers that make you say, "WTF did that come from!?"

Your test shows primers do make a difference, and proves again that, after any component change, we should treat the result as a completely new load-lot.

Jaywalker

Somebody a few days ago was mentioning a test where the brass with badly off center holes turned out to be the most accurate. You don't always get what you expect.

I was reading on a benchrest forum how a guy reamed his flashhole on a 6mmPPC
here's what he wrote:


Test #1
.058" Flash hole
Group size .190"
Avg. Velocity 3204 fps
Extreme Spread 49 fps
Standardd Deviation 20 fps.

Test #2
.068" Flash hole
Group size .156"
Avg. Velocity 3215 fps
Extreme Spread 31 fps
Standardd Deviation 15 fps.

Test #3
.078" Flash hole
Group size .125"
Avg. Velocity 3202 fps
Extreme Spread 18 fps
Standardd Deviation 8 fps.

So I reamed a few of my 204 brass to uniform the hole (.081" from .078") and will try and report my findings.

Jimno

What are we supposed to conclude from looking at the target? I'm not seeing a big difference in group size, but do see a change in POI, especially with the Winchesters.

My experience is that the primer I used in load development is the most accurate. No big suprise there.
I assume if I developed the load with a different primer then it would be the most accurate but with a slightly different charge wt.
The only way to know for sure is to develope the loads with a couple of different primers in tandem and see which works best with that particular set of variables. ie. Bullet, brass, caliber, powder and oal.
Since I don't have the time or resources to do this type of indepth scientific testing I use CCI BR-2 primers as they seem to work the best in a couple of pet loads.
Others have found other primers to suit them the best.

quote:

Originally posted by MarkL:
What are we supposed to conclude from looking at the target? I'm not seeing a big difference in group size, but do see a change in POI, especially with the Winchesters.

I wanted to show how the FGM205M outperformed the other primers I tested during this session. The difference in group size is staggering. The FGM205M (top right is .500 for 5 shots and .250 for three shots (discount the flyer please)) the WSR is .88, the FEDchampion is 1.19, the CCI400 is 1.00. That is significant in my world.

Sorry if you don't see the difference.

I just picked up some Rem 6.5 and 7.5 and will try them next.



Regards,
Jim

I'm a little confused.
To me, it looks like you have to discard 60% of your data to draw that conclusion.

Swampy_Fox,

Why?

I didn't shoot all 10shots (just 8) to show the 205Ms. It shoots like this everyday with them. No need to burn them up on this target, I've got stacks of targets that would show the same thing.

Some people are just hard to please, I guess.

Jimnno

Maybe just a difference in method.
I normally shoot my tests on clean targets so I can reevaluate at later dates.
If I had a load that put 5 touching and 4-5 scattered I would be looking for the reason.
I didn't realize it was two different loads shot at the same aimpoint.

Swamp_fox,
No problem if you didn't catch it the first time. I've done that.

Take care.

Jim

I'm a little confused on your explination as well. It doesn't really matter in this case as the point of discussion is really about switching primers.

It looks to me that the Win small rifle primer shows promise as well. It looks like you have a very tight group with a couple landing outside it. It would be interesting to watch this happen, order of shots, time between, ect. I'm not a bechrest guy at all, and for everything but ground squirrels these groups would be good. The temp of the barrel, how many shots between cleaning, and time between shots can all effect the group sizes pretty drastically.

I'm still learning about "bug holes" as I spend most of my time shooting bigger stuff, the pursuit of tiny one hole groups hasn't been the biggest priority. This is very interesting to me though as I have a bull barrel .22-250 that I have yet to find a perfect load for. Coyotes at 200 yards are still no big deal but it doesn't shoot well enough yet for ground squirrels at that range. Nate

Guys,

I shot the target in a counterclockwise direction.

Each group was followed by regular cleaning regimine, and the barrel does not copper-up nearly as much as one would think. I have a hard time getting any signs of copper on the patch, even with Tetra Copper Remover. It just doesn't foul. Strange for a factory tube.

One never knows what is happening between first and last group, that's why I shot the second group of 3 205M after shooting all the others. I wanted to see if something had changed with the rifle. Nothing changed.

Honestly guys, I never meant for this to be the do-all end-all of primer comparisons. I had some primers, I loaded them into my pet load and shot them, this target is the result.

I'm not sure it's worth the trouble justifying the target. It seems more like work than the intended fun.

JMHO,
Jim

I for one am glad you posted with a pic of what your results were. Sorry this isn't the fun you hoped for. It has me thinking I should maybe more concerned with the primer changes and let the powder be a constant.

One load I tried in the "new" rifle was a good load for another, not this one though it seems. Weird. Nate

Guys,
Spent a nice Sunday morning at the range. Tested Sierra 32 and 39 gr bullets with Benchmark and different primers, and one group of the better shooting loads with a larger flash hole.

Nothing good came of these tests. In fact the Benchmark powder dropped about 200 or so fps off the best load in I4198 (from 4170 to 3850 fps) with 4 gr more powder, and a much, much dirtier barrel.

I'm going back to I4198. Hope to get some FGM205M Primers tomorrow. I will then play more with seating depth.

I shot the Rem 7.5 and 6.5 primers and had a blown primer in the 6.5 on a below book-max load.

Regards,
Jimno