Something for you to ponder. In some of the posts below people mention they are using two different brands of powder in their rifles. One for CPT and another brand for Rams. I always try to use the same brand and powder number for different bullet weights in the same rifle. This is not always possible so I never vary from using the same brand in the same rifle.
Why ? Years ago I did some experimenting using different brands of powder while working up loads. Something clicked and I did some more checking and came up with a conclusion. After shooting a group with the first brand of powder then changing powder brands the group started with the second brand will take a few shots to settle in. In other words the first and maybe second shot of the second string of shots will not be with the group of the 3, 4 and 5th shot of that string or will make the group larger.
The conclusion may be that one brand leaves a different kind of fouling in the barrel thus effecting the way a bullet travels down the barrel.
So what do you think?

Chad. There are far more qualified to answer your post that me, but I used to do the same thing, with 2 different powders and I just use one now also. Way back when I was playing with 155's I was reading a TFT (Tabular Firing Table, it's kind of a reloading manual if you will on Arty), I was reading up on cronographing and it said that the tube would remember the prior shot, other than a 155 going a hell of a lot further that say a 140gr. alot of the ballistic stuff between the big stuff and the small are the same.

JB
Were you using smokeless with the 155?? How about some bullseye?
We had a cannon shoot when I was at Raton. It was amazing how accurate even the smooth bores were at 5 and 600 yards.
The first shot with a clean barrel is different than the next shots because of the fouling, coating or lubrication or what ever you want to call it that the powder gives.
This can also be seen on rimfire when changing brands of ammo. Some different brands are actually compatable.
How is the weather out there? -16 F here this morning. going to have to get the winter jacket out if this keeps up.
CS

Yankee, ......JB finally stopped using black powder and Bullseye duplex loads with 155's after he blew up three perfectly good 700 actions. He was a slow learner.

VARGET for all needs!!!

McAlice, I was refering to a 155mm not a 155gr. There were two different charges one was green bag (fast burning) and white bag (slow burning). The powder inside the bags was round shapped and coated with it looked like wax. The gun guys called them rabbit turds. There was two brothers and they both were about three wave lenghts to the right off. They would load rabbit turds into cigarettes and then offer them to anyone who smoked. When the powder ignited and a flame came out of the cigarette about 8 inches the Fernandez brothers would laugh like hell.

Yeah , I know. Just saw an opportunity to bust your chops. Still trying to get even for that "News Flash" post. Sounds like you guys had lots of fun in the service.

Not just a joke about the 155's. Years ago Sierra turned up some 6.5 mm 155 gr. match kings. They were long with the same ogive as the 140 Mk. Needless to say a lot of the bullet went into the case just to get the cartridge into the chamber. So I cut back on the powder like all good reloaders should do. But not enough. The first of these were shot in a 6.5 x243 I had made up in about 1990. The first shot had smoke curling out around the bolt and I had to get the boot off to get the bolt open. Ended up going to 4350 in place of the 4064 I was using at the time with the 140 and 120.
Well so much for history. The old 160 round nose Hornady would really take a ram down but accuracy was a bit rough.