Author Topic: M77 MkII Questions?  (Read 747 times)

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Offline Greysky

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M77 MkII Questions?
« on: May 04, 2007, 12:07:47 AM »
I just purchased a used standard grade M77 MkII in .243 Winchester for $329.99 from our local Gander Mountain store. It is in excellent condition, and is topped with a 4-12 power Tasco with benchrest adjustments.

Questions:

Due to rather liberal headspacing, do those of you with experience recommend neck sizing for improved downrange performance?

What bullets (brand and weight) provide optimum performance in the M77s  22", 1-9" barrel?
If at first you don't succeed, by all means try again. But if this doesn't work, give up, because there is no sense in making a darn fool of yourself.

Offline George Foster

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Re: M77 MkII Questions?
« Reply #1 on: May 05, 2007, 12:20:24 AM »
In my own 77 MKII 243 I find that partial full length resizing works out the best and my rifle has a short throat.  For loads my best loads are with the 75HP Sierra and 85HPBT Sierra using IMR4831 powder.
Good Shooting,
George

Offline Greysky

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Re: M77 MkII Questions?
« Reply #2 on: May 05, 2007, 03:56:58 AM »
In my own 77 MKII 243 I find that partial full length resizing works out the best and my rifle has a short throat.  For loads my best loads are with the 75HP Sierra and 85HPBT Sierra using IMR4831 powder.

Thank you for responding, George.  :)

My M77 MkII has a shorter throat than the .243 NEF I owned. The headspace in my M77 is also on the liberal side. So I've decided to neck size my fireformed cases for possibly greater accuracy and to extend case life.

I visited the range yesterday to check the zero on the scope, and tested the rifle with Win. 100gr factory ammo, along with my handloaded Sierra 85gr BTHP, Sierra 90gr FMJ, and Hornady 87gr BTHP bullets. At 120 yards the 100gr Win. ammo delivered a 3/8" group approximately 1" just left of the bullseye. After correcting for windage, they printed 1/2" high on the bullseye. The Hornady loads printed a 3/4" group at 1:00 on the bullseye. The Sierra 85gr loads a 1/2" group at 4:00. And the Sierra 90gr. FMJ loads printed a 2" group at 3:00 just outside the bullseye.

My NEF printed the best groups with Sierra 85gr BTHP bullets, and I think my M77 MkII prefers them as well, even though I've read that the 1-9" barrel on the M77 will perform best with 100gr bullets.

Of course, there are so many variables, my conclusions might be incorrect. Conducting further range tests should provide more conclusive results.
If at first you don't succeed, by all means try again. But if this doesn't work, give up, because there is no sense in making a darn fool of yourself.