Snakeoil
Well-Known Member
Okay, since I suggested this sub-forum, I might as well be the one to start the first thread. I'm no expert. So, looking for more experience or data.
We shoot out to 500 yds for a typical BPCR type match. But we allow centerfire rifles as long as they are pushing cast bullets. My primary rifle for this is a 1903 Springfield made in 1921 with it's original barrel. Currently shooting the SAECO 315 bullet in 170gr with a GC over 18 gr of 2400. SD for this load when I tested it was 10 fps. Shooting is done with a 10X Lyman STS scope. But the discussion is not really specific to this caliber and load, but rather what happens when any bullet passes from sonic to sub-sonic and how to reduce the negative effects.
I realize that wind, mirage, changing light and operator error all play a role in flyers. But there are some flyers that simply do not make any sense. Another thread touches on position sensitivity of powder, pressure variation and such. But one thing nobody has mentioned, and I suspect it is because not many are shooting beyond 200 yds on a regular basis, is the issue of transition speed and its affect on the bullet.
According to an article I read, as the bullet passes from sonic to sub sonic it can go unstable. The instability can affect its path. The article went on to say that short fat bullets seem to fair better than long skinny bullets because they have less of a tendency to wobble. That makes for a conflict because heavier bullets buck the wind better and the only way you make a .30 cal bullet heavier is to make it longer.
So, it there a way to find a happy medium? Has anyone found one? Is there a heavy bullet that performs better in the TS (trans-sonic) range than another? Needless to say, it is not an easy question to answer because of the previously mentioned variables. My guess is many rounds need to be sent downrange in order to build a large enough data pool to determine if one bullet works better than another in the TS range.
So, whatchya, got??
We shoot out to 500 yds for a typical BPCR type match. But we allow centerfire rifles as long as they are pushing cast bullets. My primary rifle for this is a 1903 Springfield made in 1921 with it's original barrel. Currently shooting the SAECO 315 bullet in 170gr with a GC over 18 gr of 2400. SD for this load when I tested it was 10 fps. Shooting is done with a 10X Lyman STS scope. But the discussion is not really specific to this caliber and load, but rather what happens when any bullet passes from sonic to sub-sonic and how to reduce the negative effects.
I realize that wind, mirage, changing light and operator error all play a role in flyers. But there are some flyers that simply do not make any sense. Another thread touches on position sensitivity of powder, pressure variation and such. But one thing nobody has mentioned, and I suspect it is because not many are shooting beyond 200 yds on a regular basis, is the issue of transition speed and its affect on the bullet.
According to an article I read, as the bullet passes from sonic to sub sonic it can go unstable. The instability can affect its path. The article went on to say that short fat bullets seem to fair better than long skinny bullets because they have less of a tendency to wobble. That makes for a conflict because heavier bullets buck the wind better and the only way you make a .30 cal bullet heavier is to make it longer.
So, it there a way to find a happy medium? Has anyone found one? Is there a heavy bullet that performs better in the TS (trans-sonic) range than another? Needless to say, it is not an easy question to answer because of the previously mentioned variables. My guess is many rounds need to be sent downrange in order to build a large enough data pool to determine if one bullet works better than another in the TS range.
So, whatchya, got??