ihmsa forums

as a newer member to this sport i don't yet reload,so i recently purchased a 6.5brm barrel and 140gr ammo from eabco.the mv for this is 2347 with 1712 ft/lbs of energy,my concern about this pricey purchase is if it will cause target damage and not be allowed in competition

IHMSA rules require Big Bore targets to be T-1 tempered steel plate or similar and by the rules your ammo can't cause damage resulting in penetration exceeding 1/16". Now, what velocity will cause that level of damage? The reality is that there is no simple answer. Not all T-1 or similar alloy plate is the same. And the way the targets are cut and welded can affect the temper of the steel. Some people say 2400fps is the highest velocity before damage occurs. I've seen heavy damage to targets at lower velocity than that. So it depends on how good the targets are where you shoot. It is not a perfect world and there are no absolutes when it comes to target damage.

I ran Sierra 107's in my 6BR at 2400 FPS with no target damage on several ranges. I suspect you will find that your load will be OK. Ask the match director's permission to shoot one round at a chicken. That will tell the tale.

Light weight, fast bullets tend to cause more damage IMHO.

Steve W.

Again, there are different grades of T-1 steel and other hardened steel plate
T-1 321
T-1 360
AR360
AR400
AR450
AR500
The numbers designated to each give a rough idea of their brinell harness. Obviously they will not all withstand the same velocity without damage especially if they were overheated in the cutting and welding of the targets.. The T1-321 being the softest could be damaged at 2500fps. The term "T-1" is a branded trade name kinda like "Coke"

As far a mild steel targets, the velocity level is closer to 1800 fps that will cause damage.

I've repaired enough targets to know that all those "T1" animals are not the same.