My brother is working on a 7mm STW AI load. He is using H1000, fire forming has gone well, no growth of brass measured with mic, no visible pressure signs.

We do not have access to one of those fancy Oehler's so we can not measure the pressure. However we do have an old Oehler 33, so we can monitor the FPS.

In spite of my ragging on my brother he is determined to use the 140gr Nosler BT. We are wondering if 3400 is to fast?

Thanks, Don

I wouldn't run one that fast. I had a couple of blowups out of a 7mm rem mag at 3200 fps. When I had a 7mm STW I used 140 grain partitions at 3500 fps. Nowadays I'd probably choose the accubond. H1000 is a little too fast burning powder for my taste in the STW, I had better luck with RL25.

It's not overly fast.Myself with the lighter weight bullets up to 150 grains I use IMR 7828.

3400 is a good place for that bullet weight.

+1 for 7828.

I have some A-Square factory loads for a STW that shoot a 140 Nosler BT at 3500.

Hello Don. Tell your brother, IMHO, he is treading on thin ice. The standard STW can be loaded with powder levels greatly exceeding the pressure limits for all manufactures. Unless you have had the action heat treated and pressure tested it could be dangerous. I would consult with a very experienced Smith on this one. You can already achieve 3300+ velocities with a 140gr bullet in the standard STW. I'm no expert, however, I just don't get it. Very interested in the project, but nonetheless, I'm curious.

Having said that, I wish you guys good luck. The STW is a finicky critter that takes alot of patience. Regards, Rick.

I can get there in a standard STW/27in bbl, with H1000 or Rl22, or 7828. 3300 is plenty.

I have had a couple of 140g BTs blow up at that speed from a STW at the range...8-10" holes in the plywood backing.

My 7STW was running 3380 with 150 gr BTs over 79.3gr IMR-7828. I think your OK.. but need heavier bullets to really see the STW shine..

Blygy

FWIW most max loads in Nosler#5 are in the neighborhood of 3350 with a max load of AA8700 reaching just over 3400. However Nosler doesnt show data for Hodgdon H-1000, Retumbo, or RL-25 which should all work well in this gun.
I would expect a max velocty for a 140gr Nosler to be in the neighborhood of 3450 with the right powder in your STWAI.
I would start with AA8700. It works great in my 7MM ultra.

Personally, I would rather see him using the Hornady 162 gr SPBT instead of that 140gr bomb. I predict the first buck he shoots at close range will have an entry wound that will look like an RPG attack.

i ran an 140 NP into exactly one buck at 80 yds, mv was 3440 IIRC and like i said it was only one. the rpg attack was out the offside however the deer died right now. after that i ran the 140 np to the same MV with great results. when pushed that fast the NBT just does not stay together IMHO

The 162 Hornady has proven to be way softer than even the 120 Ballistic tip for me. Haven't tried the Interbond. The Hornady shot great tho.

Stay as far a you can from the 154 IB STW loading.What a pain in the azz that bullet is.I finally found a half azz hunting load but accuracy is no screaming hell and performance on large critters was dismal at best.

Complete waste of good powder.

A friend of a friend claims to have 140gr triple shocks motoring just shy of 3700fps, I have no reason to doubt that info.

I have my STW pushing 160gr partitions right at 3200fps. Could push a little more but I'm plenty happy with what I've got now.

Done the RPG thing and never will again. Stuck one 150gr BT into the brisket of a midsized whitetail and could have filled the entry wound with a grapefruit.

alot depends on your barrel, custom barrels are normaly faster at the same pressures.
My lilja barreled bansner puts the 140 NB out at 3552 fps, thats with 86gr. of H1000 with absolutely no signs of pressure. the 160 accubonds run 3340 with 94 gr of WC872, again (in cool weather,872 is temp sensative in smaller cases than its designed for) with no pressure signs whatsoever
RR

I have found you need a really good barrel to get a good STW.Never have been impressed with that cartridge unless it was custom tubed.fwiw....What I mean is they can be picky to load for.

Actually he arrived at the same/identical load. Same muzzle velocity.

here are some of Layne Simpsons loads published in the april 1995 edition of handloader.


140gr Sierra SBT, H4831, 78gr-81gr, 3348-3417fps (decently reasonable)
140gr Nosler BT, RL22, 78-80gr, 3404-3463fps (about right with current data)
140gr Nosler BT, H1000, 86-88gr, 3373-3516fps (getting hot in here)
140gr Nosler Partition, 7828, 80-83gr, 3407-3498fps (even hotter)
160gr Speer GS, RL22, 76-77gr, 3165-3219fps
160gr Speer GS, H1000, 80-85gr, 3149-3319fps (smokin)
160gr Partition, H5010, 87-90gr, 3182-3311fps, (wow)

A-Square factory loads in 26.5" Custom 700, Schnieder barrel, wow, look at these speeds.
140gr Nosler BT, 3512fps
160gr Partition, 3315fps
160gr Sierra SBT, 3303
RR

Thanks for posting that Ridge Runner.