Range day

[Bill Hollinger]

I worked the range today and took a couple of toys with me. I took my Winchester M1 Garand and my S/A M1A. At 100 yards with the M1A I got a three shot group that could be covered with a quarter. The only thing bad is the three shots were four inches high from the last range day. Nothing changed, nothing moved, except for one thing; The last range day for the M1A was back in April when the temperature was very nice and in the mid to low 70s. Today the temperature was nearly 100*. Could this have made such a difference?

The Winchester M1 shot quite nice with a three shot group of 1-1/2 inch at 50 yards but five inches low! So I moved up to the 25 yard line and shot a great group, adjusted the rear sight and got a three shot group of about just -1 inch. Then it was back out to the 100 yard line and it shot dead center POA with about a four inch group. The rear sight seems to be high to me. It is six or seven clicks off bottom. Does that seem right?

All in all, a great day at the range and got paid for it!

Information

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[Kirk]

Six or 7 clicks from bottom is just fine. One of my rifles is 10 & the other is 15! A lot depands on how the gas cylinder is fitted.

[Bill Hollinger]

Thanks Kirk. I kind of was leaning that way also but I always thought three clicks up for battle zero was the setting. I have another M1 that I will take out next range day. It is the one I built for my son's 17th birthday. It shoots low at 100 yards going off the three clicks off the bottom theory. Thanks so much!

[snakehunter]

Somewhere I read that a 10 degree change in the propellant temperature can result in a 100f/s change in velocity

[gunner]

Hi Bill, snakehunter has right with his comment. I have a difference from about 5" between shooting at +22C° and -7C°at 300 metres with my .308 Win. . So differences in height by differences in temperatures are normal. But i think you know these as well.

Regards

Gunner

[Bill Hollinger]

I kind of thought four inches at 100 yards a bit high for the temperature change though.