Subsonic expansion testing

popper

Well-Known Member
40sw@7yds, 99/1%Zn 175Lee TC with lube grooves and LLA. Nice rectangular holes from ones that came out undersized (shoulda been 401). Backer is 1" fiber wall board - soft!
 

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Spindrift

Well-Known Member
I recently bought a can of Vectan Ba10. This is the fastest burning powder in the Vectan line, listed burning speed similar to Bullseye. It is a low density, extruded single base. The idea was, it might prove useful for these subsonic loads with relatively light bullets. I shot two groups with the MP-Hunter, and 6- 6,3grs respectively, in my S&L 30-06.
Range was 70 yds.

The 6grs load needs looking into. I pulled one shot high (shows on the target). The remaining four in a connected vertical string. 6,3 grs was not awful either. I’ll have to shoot this powder some more, it seems to have some merit. I didn’t chrony these loads, but they were all very quiet (shot with a suppressor).

49BC2578-7CA3-420F-AC10-787C5EDA266F.jpeg
 

Ian

Notorious member
Flyers are yawing. Try 6.1 maybe? Looks like 6.3 is hitting them too hard at liftoff.
 

Spindrift

Well-Known Member
You're right, I didn't notice.
I also think 6,3 is a touch to much. I'll try 6,1!

If they group well, I didn't mind a little yawing, actually. Potential uses for me, is varmints- so I don't really need deep, linear penetration.
 

popper

Well-Known Member
1% zinc cast fine @ 750F. I later added 1% Sb to get the dia fatter so tumbling would go away. I should have PCd them with just the Zn. Was just an experiment to see the effect of Zn.
 

Kevin Stenberg

Well-Known Member
By yawing. Are you talking about part of the bullet hole being torn on an edge. An the opposite side of the hole is clean cut?
Is that caused by a non stabilized bullet? Wrong twist for the bullet length being shot.
 

fiver

Well-Known Member
yeah they are wobbling.
if you look at the picture on the left, the top hole is pretty much textbook.

sometimes a loose backer and shooting at an angle will give that same impression.
but that black smear is a dead giveaway, especially when you see it in a different place on the other holes like in the picture on the right and those two top holes.
 

CWLONGSHOT

Well-Known Member
I have been doing alot of this testing with a buddy. Shooting into wet magazines as news papers are largely becoming a thing of the past!! :headbang:

We had a SHOKER just yesterday!! This is a MP mold 360-220. Cast in 30:1 Well thats taking my Rimfire range lead as "pure" & adding tim to get 30:1. Then powder coated & gas checked. Fired @ 2250 in a 358Win into a 50y box.

CA77808A-2536-421C-8683-30D6169CE57A.jpegA8DD6F58-F9D2-4380-B367-72CA42B3F3AB.jpeg706070B0-AA31-4314-AD9C-101C1670F8EE.jpeg2705D2D3-9FD7-4613-BAB6-6B69F91AC664.jpeg
 

CWLONGSHOT

Well-Known Member
wow, nice!
I never woulda expected that from 30:1 alloy.

We have shot MANY at 20:1 and 10:1. But always slow from a 357 Maxi. He got a wild hair and loaded some to much faster in the 358 Win!

These are 20:1 @ 1500fps
C906BD7B-4F0C-4329-9FFB-533F596F20BD.jpegB41EFB7D-3F33-424C-87AE-2EC0358EDD8C.jpeg

There are 10:1 @ 1500fps
D1F134AB-492A-48F2-924D-D8E1BD7EE832.jpegE496C06D-56EA-45AA-A93B-06387C54D2F2.jpeg

These are 20:1 @ 1100 fps. One started expansion yet three more, didnt at all.
6B3EBDE2-7B7D-4EAE-AE45-458BC9DA22A2.jpeg
I enjoy the learning!!

CW
 
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fiver

Well-Known Member
I'm not super surprised at the 30-1 [ish] doing that.
it has long been the choice for handgun hollow points because it retains so much malleability.
the slightly higher tin content than what the factories used in the smaller Winchester dash cartridges gives it just a hair more rigidity.
 

wquiles

Well-Known Member
But I am still amazed at how well it handled the 2250fps speeds with powder coating - probably the "larger" bore of the 358Win allows the "softer" allow to handle the pressures. But I also suspect the powder used contributed to lower pressures to help the allow+powder coating to do their job. What powder and amount are you using?
 

CWLONGSHOT

Well-Known Member
The velocity is where my suprise is focused.
I have sent softer a lil faster many times and yes this powder coat is almost magic.

30:1 has been a factory mix for a long long time! BUT not at these velocities!! The HP is small likely a large part
 

Spindrift

Well-Known Member
Thanks for a great post, @CWLONGSHOT !
I have the MP 220 HP as well, for my Whelen. I have, so far, only done some accuracy testing with subsonic loads- good accuracy at 100m! I’ll do some more powerful loads as well, when I get around to it. It certainly looks like you have a potent and capable load there!

My .22lr/airgun range scrap is BHN8 when newly cast, regardless of air cooling, or water dropping. It age hardens to about BHN 11-12. It casts really well. A very good allround alloy, I think! I’d guess around 2% antimon, and no arsenic. It is from a range where they mostly shoot RWS .22lr.

I have sent a lump of alloy to an engineer on a Norwegian forum, who offered to do an alloy analysis with his professional equipment, I’m awaiting his results.
 

fiver

Well-Known Member
I'm interested in the alloy too.
me and Glen had a kick around speculating on 22 lr alloy.
he maintained it had about 1-1.5% tin and I leaned towards it having antimony.
I had to kind of give in some after melting down a bunch of it and using it to cut my ww alloy 3-1.
those ingots still got a shine to them even 8-10 years later that antimony alone can't account for.

but we both seemed to agree either alloy was sucking in some copper and if it was mixed with [say WW alloy] it really helped kick things up a notch even when run soft.