RFI, soft points vs FMJ on steel, what gives?

[Adrenaline_6]

Velocity is key. Is that reload hot? <2850fps is usually what you want at target.

[ViniVidivici]

It's in the upper 1/3rd of 5.56 data from Hornady's site, been using the load as a 62gr FMJ for years, 24.4gr H335. Shows 25.4 as max.

No signs of excess pressure, brass gets loaded 5 times, no issues.

Used the same charge for these 62gr SP. Different bullet type, yes, but not drastically different, as far as how it should affect velocity, I wouldn't think. Primers and brass look same, no high pressure signs.

OAL is same on both these rounds too.

[Clint]

FMJ tends to pancake on steel, while the SP / OTM tend to mushroom.

This mushrooming effect blasts material out of the crater.

We once shot some 6.8 SPC OTM loads through mild steel that made super caliber holes.

The holes were large enough to drop the entire case through.

Think about that for a minute.

[JediGuy]

…We once shot some 6.8 SPC OTM loads through mild steel that made super caliber holes.

The holes were large enough to drop the entire case through.

Think about that for a minute.

Sometimes I wonder if 6.8SPC2 really was a missed opportunity.

Separate from that, maybe there US should stop acting like we are abiding by international agreements to which we are not even a party.

[ViniVidivici]

FMJ tends to pancake on steel, while the SP / OTM tend to mushroom.

This mushrooming effect blasts material out of the crater.

We once shot some 6.8 SPC OTM loads through mild steel that made super caliber holes.

The holes were large enough to drop the entire case through.

Think about that for a minute.

Thank you, this is now beginning to make sense to my brain!

Just so wierd...I mean, it's common knowledge that AP, and really high velocity stuff up close will wreck steel, but I've never heard or read that SPs or OTMs were detrimental and should be avoided.

Seems like it should be the same level of common knowledge...is it, and I've just missed hearing it?

[Pappabear]

It sucks when you beat up your steel. Velocity and bullet make or break. I tried XM193 one time right after getting some Bowling Pin targets. Thought these shoot alright but nothing that different, then I went home:


It was brand new at the time, 5 holes through and through. This target sits on the side of the house now, but it was once special.

PB

[Disciple]

Soft points typically have a closed base, sometimes with a thick jacket. FMJs are typically open base. Pure conjecture but maybe the structural integrity of that base section plays a role. Mill off the SP jacket from the base only and see if it still craters like that?

[georgeib]

Soft points typically have a closed base, sometimes with a thick jacket. FMJs are typically open base. Pure conjecture but maybe the structural integrity of that base section plays a role. Mill off the SP jacket from the base only and see if it still craters like that?

I was wondering the same thing.

[markm]

Mill off the SP jacket from the base only and see if it still craters like that?

That's some crazy shit I might do. But you're changing the bullet weight and thus the results would still be speculation if the pocking was gone.

[Disciple]

That's some crazy shit I might do. But you're changing the bullet weight and thus the results would still be speculation if the pocking was gone.

I suppose velocity would go up, so if cratering were simultaneously reduced that would seem even stronger evidence the closed base is a factor.