Different Brass Changes POI Drastically

[Jim Tarleton]

MEHavey,

One of the more interesting papers I have read in years. Thanks you, very much. It leaves me in the dark about my recent POI issue, and fundamentally refutes my longheld and obviously incorrect belief about the relationship between POI and velocity.

I have my own range, and it is now a max of 150 yards, currently set up for 100 yards. I intend to try the incremental load test at 100 yards to see if I can garner any useful information. It sounds very reasonable to me, and beats my old tried and true method of firing a couple of hundred rounds loking for an accurate load. I have worn out the gilt accuracy of barrels looking for that elusive "magic load", often without success.

I have lucked out. I recently (within 1 year) built a 22-250 that shoots my first test load into very small holes with zip mystery flyers. This puppy just keeps on putting them in the same hole shot after shot. If I can put the dot (Lyman 24X w/micro-dot) on it, the bullet will hit it. I also have a 7.65mm rifle with a 18" barrel that shoots MOA with a peep sight from rest. These two rifles are rarities for me. Typically I spend a lot of time finding an accurate load.

Thank you,

Jim

[Allen]

" I can see my daily firing schemes going down the toilet. Has anyone tried the reloading of primers using match head components? Is it even legal? "

Who cares if it is legal? If it could even be made to work I would think it would be more trouble than it is worth. Also, may only work with a select few types or powder including black powder. You have that big firing pin dent too to contend with on trying to reload a primer. If things get this bad I will go to black powder weapons or some "creative" shotgun loads. Shotgun primers are still available at this time.

[MEHavey]

It leaves me in the dark about my recent POI issue, and fundamentally refutes my longheld and obviously incorrect belief about the relationship between POI and velocity.

Jim,

What the author states is that a slower velocity bullet will still be in the barrel as the barrel rotates upward from recoil past the point that a faster bullet would have already exited. The slower bullet is therefore actually launched at a (very) slightly greater upward angle compared to its faster cousin.

At short ranges that means the slower bullet will impact higher on the target for the same POI, although at longer ranges the faster bullet will eventually win out and drop less for a given range.

This effect is very pronounced in handguns, as evidenced just this weekend where I had a whomp`em stomp`em 158gr JHP .357 going out at 1,500fps striking dead center at 25 yards, while a 158gr LSWC going 750fps from the same gun 5 minutes later struck five inches higher. (Naturally, that slow LSWC would be on a football downward arc by 50 yards, while the JHP doing 2x the speed would still be climbing.)