First shot flyer

I am trying to work up a load for my Marlin 45-70 CB. So far I've used Rapine 250, Lee 340, Ranch Dog 350, Ranch Dog 425. I've also tried Reloader 7, 4198, 3031, Varget, and now 5744. Best results so far is Ranch Dog 350 and 5744. BUT I am having a heck of a time trying to sort out why I constantly get a FIRST SHOT FLYER. And its always high bringing a 2 1/2 to 3 inch group out to 5-7 inches. If I shoot 4 five shot groups in an evening, letting the barrel cool between groups, the first shot of each group will go high, the remaining 4 will cluster into an acceptable group. Velocity is just under 1700 fps. If I ever get this worked out I plan on using this for Lever Action Silhouette. Thanks in advance for your suggestions. Doug

I too had that problem with my 1894 Marlin until I added a credit card shim to be directly under the barrel at the end of my forearm. That bit of upward tension helped me by getting rid of the first shot flier. Try it you might be surprised.

Is it a "clean" cold bore or a "fowled" cold bore?

Your post indicates a fowled bore, but you never know. Adding a little pressure to the barrel can't hurt. I would also recommend you check to make sure the buttstock is properly tightened.

These are always from fowled barrels. I throw a round or two at a gong before I get serious at the bench. Doug

Is the first shot flyer always in the same place? Are the other 4 shots making a round group?
How is your boolit to barrel fit?

Try a dry patch through the barrel between groups. Vary your charge weight up and down and see if that makes a change. Try 4227.

I had a Winchester '94 Oliver F. Winchester commemerative in 38-55 that did that same thing. The first shot out of a cold barrel would be 8 or so inches high, the second half that and then it would shoot good groups. Had it cryotized (freezing the action) and it stopped until I warmed it up good the first time out and then it started doing it again. Couldn't figure it out, but put a new barrel in it and it contined to do the same. Got rid of the action and put the barrel into a pre-64 action and no problem. Figured it was something to do with the action, possibly the threading or stresses that couldn't be relieved. Pretty frustrating when you have to always shoot a Cowboy long range match starting from a cold barrel.
McLintock