Got a scope, need an idea for dial in.

[ReAX222]

I put my bore laser in, and the windage is on. How is the dwell on the 300? Will bore sighted elevation get me on paper at a 35 yard range? I only have 5 rounds built to try out 11gr of 4227 with a magnum primer and would like to be on paper with the first round so I can get it set with them.

[skurvy]

It will probably be next weekend before I fire my first shot in my 300 whisper but their shouldn't be enough drop at 35 to worry about.
I plan to eyeball bore sight mine for 50 yards and go from there.

Where did you get your 4227 load data from? I'm curious about that powder.

[ReAX222]

Originally Posted by skurvy

It will probably be next weekend before I fire my first shot in my 300 whisper but their shouldn't be enough drop at 35 to worry about.
I plan to eyeball bore sight mine for 50 yards and go from there.

Where did you get your 4227 load data from? I'm curious about that powder.

H4227 and IMR 4227 are supposed to nearly identical in burn rate (m/s2 not just in the list). My Sierra manual has 221/300 load data back in the single shot pistol section, I had to adjust the seating depth to my magazine, but it's working so far.

I started at 10gr with CCI 500 primers. It short stroked my AR, so I stepped up to 11gr. It's still short stroking I think because it will feed each round, but will not lock open on the last round. I'm out of small pistol primers so I'm trying magnums. I want to say that Sierra recommends 10-16grs of 4227, so I think I'm still in the safe pressure range.

[ReAX222]

I sighted it in at 20ft, then tried it at the range and couldn't find my laser dot. I dropped the crosshairs a full rotation of the knob, probably 40 or so MOA and still couldn't find it. I shot it anyway and it was still 2" high at 35 yards. I can only imagine the work it would take to calculate sight drop on an a2 upper to go from close to intermediate ranges.

Also I was wrong on the SSP section in my sierra manual. I read here I believe that 300/221 loads like a 357 magnum and I started at 10gr with 4227.

[Rikky Lee]

It isn't easy - but the way you did it is the best. A close target and a center hold and then take it back a distance for a group test.

100 yards/meters is my benchmark now for grouping accuracy.