9mm Semiwadcutters: is 1088 fps the End of the Road?

[Swifty Morgan]

I'm loading 125-grain 9mm semiwadcutters from Missouri Bullet. The powder is BE-86. The primers are Winchester small pistol.

The closest published load I could find was for cast 125-grain round nose bullets, so I went with that, changing the OAL somewhat to accommodate the longer semiwadcutters. I chose 1.160", whereas the published data (Alliant) says 1.120". My bullets are 0.06" longer than the round nose bullets I have on hand, so my assumption was that I was pushing things a little by only increasing the OAL by 0.04".

The published load goes up to 5.7 grains at 1179 fps. I was surprised to see a velocity that high.

I tried 5.2 grains, and I got 1082 fps. I thought I could do better.

I tried 5.3 grains and got an average of 1088 fps with a very low spread of 14. Only 4 of the 5 test rounds showed up on the chronometer. I tried 5.5 grains, and I got 1099 fps with erratic speeds. The spread was 51. Again, only 4 shots registered.

I was hoping I could get something like 1125 out of this short barrel, but it appears that adding powder isn't doing much, and the spread is going crazy.

Am I at the end of the road, or is there anything else I should try? I could try shortening the OAL a little to increase pressure. I am not seeing pressure signs.

It sort of looks like if I can't get any more speed, I should go back down to 5.3 where the spread was low and the speed was acceptable.

[Nick_C_S]

It seems to me your bullets are zipping along pretty good.

If I was in this position, I'd first figure out why my chronograph is only reading 80% of my shots. I took my chronograph to the range today. Shot about 100 rounds over it, and didn't get a single missed reading. It's important to get it aligned properly so the bullet passes over both sensors.

I'd stick with the same recipes and try to gather more data.

At that point, I'd also check for leading. I have these MoBuCo 125 LSWC's and tested a few. Ran into leading (with a much more mild load than yours) issues. I don't shoot 9mm much at all and set down the project - that was like six years ago . Maybe I'll get back to it again some day.

[Swifty Morgan]

Thanks for the info.

I didn't think about leading. This is a short Glock barrel, and they say they don't like lead. I just took a look. It could use some cleaning, but I don't see anything weird in there. I'm not really sure what a barrel looks like when it's starting to lead up. Supposedly, these things are safe in Glocks, but then that's a good thing to say when you're trying to sell bullets.

Guess I'll buy the coated bullets next time.

I don't know what's happening with the chronograph. Maybe it wasn't happy with the lighting.

[Nick_C_S]

Maybe it (the chronograph)wasn't happy with the lighting.

I always do my chronographing first thing when the range opens (08:00). My range is covered and orientated in a way where the shadow of the cover will cross into the diffusers by about 10:00 or so. It's nearly impossible once Daylight Saving time ends - but I digress.

Point is, I get the most consistent readings when the diffusers are bathing in sunlight.

[74A95]

How long is your barrel?????

[lll Otto lll]

Originally Posted by Swifty Morgan

I'm loading 125-grain 9mm semiwadcutters from Missouri Bullet. The powder is BE-86.

Those bullets are actually 128 grain.
At 1088 fps that gives you a PF of just under 140.
If you want more, I'd suggest a jacketed or plated bullet.

[Swifty Morgan]

Glock's site says the barrel is 3.43".

[74A95]

Your velocities are not a surprise because;

1. You're not at full published load weight so you should not expect them to be at the same speed as the full published weight.
2. You're loading long. That will decrease pressure/speed.
3. You have a short barrel.

Given the small sample of rounds you've tested, I suggest that you can't say with confidence that increasing powder gains no velocity. Are you loading these rounds with different powder weights all at the same time, or during different loading sessions?

Why does maximum spread matter?

I've loaded 5.8 BE-86 with 125 grain jacketed bullets and recorded 1300 fps from a 5" Kart barrel.

[reddog81]

Your load is .2 grains off the max and you're only 25 FPS away from what you were expecting with the short barrel. That's not surprising at all.

Making small adjustments to a powder measure is going to have some impreciseness built into the system. After rounding 5.3 could actually mean anything from 5.26 to 5.34. And 5.5 could mean anything from 5.46 to 5.54.

Additionally 4 rounds is a pretty small sample number. You can start to see were the average FPS is going to be, but any extreme spread or standard deviation figures are likely to change once more rounds are put downrange.

Realistically 5.3 is probably as good as anything else but more testing wouldn't hurt.

[Swifty Morgan]

I don't expect the full speed the published load mentions, but I thought I might be able to get 1125.

I can't be sure I'm "loading long." These bullets are longer than the only 125-grain lead bullets I have. I don't have whatever was used in the published load, but I would think most round nose bullets are similar. The way I'm loading them now, the volume of the cartridge is probably smaller than it was in the published load.

I am doing different weights in different sessions using a good beam scale. I'm not creating large numbers of cartridges because I don't want to use up my lead on testing.

I mentioned the big increase in spread because I thought it might be important.

1. You're not at full published load weight so you should not expect them to be at the same speed as the full published weight.
2. You're loading long. That will decrease pressure/speed.
3. You have a short barrel.

Given the small sample of rounds you've tested, I suggest that you can't say with confidence that increasing powder gains no velocity. Are you loading these rounds with different powder weights all at the same time, or during different loading sessions?

Why does maximum spread matter?

[Swifty Morgan]

Before giving up, I decided to try shortening the cartridges. I went from 1.160" to 1.140".

I got this:

# Velocity Ft/lbs Power Factor Date
5 1129 353.76 141 8/15/20 6:50 PM
4 1118 346.90 139 8/15/20 6:50 PM
3 1124 350.63 140 8/15/20 6:47 PM
2 1095 332.77 136 8/15/20 6:47 PM
1 1098 334.60 137 8/15/20 6:47 PM

Average: 1112

I can't see anything wrong with the casings. There is a barely perceptible bulge, but it doesn't seem much worse than it was with the longer OAL. I could jam one of these casings into a cartridge gage if I pushed.

I should have waited for my new barrel to arrive. It slipped my mind. Now I'll have to do this over when it gets here. Anyway, it looks promising.

Hornady's 2007 manual says Power Pistol was their pick for 9mm, and BE-86 is Power Pistol with a flash suppressant, so maybe this is the powder to go with instead of switching to No.7. Lyman's manual says No.7 was actually developed for 9mm, which is interesting.

I could swear BE-86 feels less snappy than No.7. I don't know if it's possible to feel a difference between two powders at similar velocities.

[74A95]

What barrel did you buy?

[Swifty Morgan]

I went with a Storm Lake. I have one in 10mm, and it seems okay.

[pete2]

SWCs are generally used to cut nice round holes in paper, Not for max. loads..