A question to the experts

[gunner]

Hi to all,

I have a mysterious problem with a load for my LE. I use a 130grs H&N bullet with 13 grs of Trail Boss powder. That is a good load for 100m shooting, but the problem is always the first shot . He sounds a little softer and goes around 2" deep. The rest is always well placed and gives a nice group. Then when i wait for 10 or 15 minutes to take the next ones the same effect again.
Any idea?

Regards

Gunner

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[MEHavey]

My thought (knowing nothing than given above) and assuming no cleaning between strings:

The first shot is low due to a cool barrel unwarped from any undue stock contact. It hits where it hits.

The succeeding shots in the string are now coming from a warm(er) barrel which has warped (ever-so-slightly) into some tip-pressure from the stock -- and hits consistantly/slightly higher than the first.

Test #1: Get some chrono readings. I wager the first shot is not that much different velocity-wise than the rest.

Test #2: Fire 4 strings using 2 targets: Left target for 1st shots, right target for all succeeding shots. I'll wager again you'll have two different -- but "ok" -- groups.

Test #3: Fire 5 rounds -- but 10 minutes apart. I'll (lastly) wager that you'll have one group.

[gunner]

Hi MEHavey,

thanks that sounds logical. I`ll do the test`s and think thats the reason why.
Send you a post.

Regards

Gunner

[Kirk]

Barrel temp should have no effect on how a round "sounds" especially after only 1 round. I believe Trail Boss is not supposed to be position sensitive but from your description, that's what it sounds like. The powder in the first round is positioned differently than the following rounds, hence the different report. If possible, try some 2400 powder or even a max load of Trail Boss & see what happens.