Need some help from someone smarter than me...

[toasty]

So I have been developing loads for 3 different custom rifles this spring. A 260 Rem, 243 win, and 204 ruger. I clean the gun, shoot a single fouler shot and then I'm getting excellent groups on shots 2-5, they start to open up from there. With the great groups I decide on my load, the problem is when I shoot them again 10-15 shots after cleaning the group size usually doubles or more. Here is the question, are you guys doing development on fouled bores? Can I expect my best groups on shots 2-5 to be my best groups when the bore is fouled? I feel like I'm chasing my tail.

100 yard 4 shot group - 260 Rem 123g Lapua Scenar IMR 4350



100 yard 3 shot group - 243 Win - 80g Berger Varmint - IMR 4064

[futuretrades]

My routine is, when the rifle is clean, I shoot between 3 and 5 rounds down the tube before testing my loads, to foul the barrel. But I am doing this with small caliber, 204, 20VT, and 223. A guy I know that used to compete, told me that his first 3 rounds were in the dirt to foul the barrel, before shooting his targets. I don't know if I am any smarter than anybody here, just my routine.

[Bill K]

Over the years, depending on the rifle and what I am hunting, I have always first seen where my first shot from a cold barrel is hitting, as that is what it will be when hunting larger game, etc.
As for target grouping, I have always fired at least one fouling shot, then go for group, as targets/grouping is concerned.
Just my routine. I really try my best to keep it simple and easy. Bill K

[toasty]

Over the years, depending on the rifle and what I am hunting, I have always first seen where my first shot from a cold barrel is hitting, as that is what it will be when hunting larger game, etc.
As for target grouping, I have always fired at least one fouling shot, then go for group, as targets/grouping is concerned.
Just my routine. I really try my best to keep it simple and easy. Bill K

Agreed, that is what I have done for many years. However, all three of these rifle are pdog rifles, I will shoot between 50 and 100 rounds in a day and before the next cleaning. I got good groups in the first few shots after cleaning, but if they are opening up once the barrel is fouled where I will do most of my shooting, have I wasted my time? Are you seeing groups in the first few shots in a clean barrel be a good indicator of groups at 30 rounds?

[Jim White]

I shoot foued barrels becaus they're going to be that way in the field. I refoul with a minimum of 5-shots and up to 10-shots if changing powder types.

HTH,

[MZ5]

Like the others, I foul with 'a few' shots to ensure POI stability. Exactly how many that is depends upon the barrel, but a few will usually do it.