Worst load ever

[clearwater]

Had a great day at the range with a buddy. Both of our new loads for deer season proved accurate and took little time to sight in.

Then I said, let's shoot some of these cast bullets loads for fun and off hand practice. Buddy fired several, but we could see no holes in the paper (16x20") no matter if he aimed high or low, left or right. We did see bullets impacting the sand behind. They were making it out of the barrel.

Moved target from 100 yards in to 50 yards. My turn. Shots varied by over a foot in every direction. A 2 foot pattern at 50 yards!

The load in case you want to sandbag someone
WW 30-06 brass, multiple firings
CCI Large Rifle Primers
Lasercast 115 grain plain base cast bullets sized to .309, Alox tumble lubed
Trail Boss Powder about 14 grains measured with Lee Dippers
No crimp

We switched to some 170 grain gas checked laser cast with weighed charges of 2400 and got about 2MOA at 50 yards and salvaged my ego, some.

 

[KinleyWater]

Sounds like your ready for fall turkey.

I don't have a lot of experience with cast in rifles, but I know that sometimes if lead is too hard, it won't obturate properly. Also may be that the bore is slightly large, and a .309 bullet may be just a tiny bit too small. Or, maybe TrailBoss just sucks for that load.

 

[clearwater]

I think you are right, there was not enough pressure to fill the rifling, too little powder, no crimp. Also the dippers aren't not very precise in my hands so charge weight varied. When I used the heavier bullets of the same hardness/manufacturer, with a carefully measured higher charge/pressure, things worked as they should.

I just didn't think it could be that bad! I shoot a bow/handgun/shotgun better even without practice.

 

[KinleyWater]

Well, a little bit of a lot of things adds up quick. I like using the dippers when reloading 38 SPL with 700x, mostly because it's easy, and I found one that throws a consistent weight. Beyond that, I tend to use them to charge a fill pan on a scale.

 

[RL338]

I had the same issue when I started shooting cast out of the 458WM. Being powder coated you didn’t need gas checked is what I was told. After a dozen rounds at 2300fps they were flying all over the target. I believed the barrel got coated from the painted bullets and they weren’t sealing and engraving the rifling. Slowed them down and everything was fine.

 

[clearwater]

Tried some more reduced loads, this time in 25-06. Once again the Trail Boss is found lacking.

With 115 grain plain based cast, only 3 of nine hit the target paper and those key holed (see photo right side).

With 120 grain jacketed 2nds with charge weights going from 14 grains to 19 grains, it produced a shotgun pattern (Top Left).

When I finally shot 3 shots with IMR 4227 and 87 grain jacketed bullets I got a nice little group. (Bottom Left)

It was a hot day and the barrel heated up quickly with the last load making the barrel too hot to touch after 3 shots.

 

[RL338]

Blue Dot is my friend for reduce loads with cast or jacketed bullets.
I’m thinking your twist rate might be too slow for the 115’s and 120’s at a low velocity.

 

[TackDriver284]

It's possible your rifle does not like cast bullets and likely a slow twist to handle the heavies as RL338 mentioned. What is your twist?
Possible you can try another load using 115 grain jacketed bullets and a good rifle powder to confirm on the keyholing issue. Cast bullets may be the issue.

 

[clearwater]

It is a 1 in 10 twist.
A 25-270 my Grandad built, he left me a lot of cast bullets so I assume he was using them too, tho they may have been for another rifle. The hunting load he used was 115 Partitions and I use 117 grain SST's or 110 Accubonds (when available). My grouse load for it uses 100 grain Sierra Match bullets and SR4759 and that gives me minute of grouse head at 25 yards.

I'd bet you are right about the long bullets with slow speed. As others have said, the cast even more problematic by not expanding into the rifling under light pressure. I have several pounds of Trail Boss, trying to find a use for and 4759 is discontinued. I don't have blue dot, but I have some fast powders I will try. Am amazed at how much difference powder/velocity makes.

 

[KinleyWater]

That's keyhole all right. That suggest a velocity or twist rate mismatch, or perhaps some of the projectiles are either undersized or out of round. If you have not already, I would suggest mic'ing a handful of the bullets to see if they are the correct O.D.. You can check for out of round by watching the way they roll on a known flat and true surface (or something close to it). You should see a wobble or up and down motion if they are out of round.

I know only one individual personally who uses Trail Boss. He only loaded 45 Colt and 30-30 with it, but told me that lower charges by case volume tended to produce poorer results. I don't know the reason, and neither did he. However, if he is correct, I expect that even 19 grains of Trail Boss is not sufficient for the 25-06 case (I expect it has something north of 60 grains capacity H2O?).

*EDIT* Caveat Emptor - I do NOT claim this individual was any sort of load wizard.