ronlaughlin

Yesterday whilst investigating leaky primers, this targets was shot. The shots were made from top target to bottom target. Four shots at the top target; three shots at the next two. It was about 50 degrees. Elevation was about 4900'. No swabbing between shots was done. No waiting between shots; the shots were made as quickly as the rifle was reloaded; the barrel became warm, but not 'hot'.

The flame channel in the breech plug was enlarged to 5/32". The breech plug was shortened 0.020" so to utilize an o-ring under the primers. The flash hole was 0.033" at the beginning of the shooting.

The rifle was a 45 caliber Omega; the load was 200g Shockwave, Harvester light blue sabot, and 115g Blackhorn.

The first shot from the cold clean rifle/breech plug is the lowest on the top target. Curiosity led to a fourth shot, after the second, and third shots were close.

cayugad

now that is interesting. Note the difference in group size and location of hit. And you being an accomplished shooter, I tend not to blame the shooter. I would be interested in seeing that same experiment repeated and see what the group dynamics are. But reverse the order. Do you think that because the W209 were shot last that, could that have effected the shot placements and group size? Or did the rifle seem to load about the same, shot after shot?

Muley Hunter

That's why I use Federal primers.

Semisane

I agree, it is interesting. And also find group location a bit of a surprise.

My take is the primers seem to have little effect on accuracy in this case. Throw out the first cold/clean barrel shot as being typically a little bit out of group and you find the first two groups are virtually equal, the the third group (on a hotter barrel) starting to open up a little.

If you do repeat the experiment, consider shooting one fouling shot then alternating shots with each primer. Shoot the first shot on target 1 with the STS, the second shot on target 2 with the 209A, and the third shot on target 3 with the W209. Then repeat the alternating sequence for shots 4, 5 and 6, then again for 7, 8 and 9. That should eliminate barrel heating as a factor.

Muley Hunter

Yes, but the STS primers have that blowback problem. Of the three the Feds seem like the best choice.

super_hunt54

Ron, I just started using that Blackhorn and I noticed right off the bat that, while it does shoot 10 times cleaner than Pyro or T7, it does carbonize the hell out of my channel. Granted that's easily cleaned in mine with a quick twist of an 1/8" bit but I am sure that effects my burn rate. Does yours get "gunkd" up like that with the Blackhorn?

Muley Hunter

It happens to all of us using BH. I'd rather have that than a crud ring.

super_hunt54

Yeah but what I am wondering is, do you think that is why his groups possibly opened up there at the end? Combination of heated barrel, fouling, and a carbonized flash?

Muley Hunter

I won't speak for Ron, but my guess is he knows how to avoid all those things.

ronlaughlin

Certainly possible! Maybe even probable. Another possible reason is shooter fatigue.