# Ruger 77 MKII - Accuracy questions - powder burns on brass



## Oldstick (Jan 23, 2007)

...  stuff from another similar thread deleted....

I have one in .308 and haven't hit on a very accurate load for it yet, but I am still in the process of trying hadloads, and such.  Also have been searching around for the easier things others may have done to improve theirs.  While searching, I read where headspace and bolt lockup is often a problem with the MKII. 

So that leads up to a question. I notice each fired case has a powder burn outside the neck about an eighth inch wide and from the rim halfway down to the shoulder. This is not all the way around the rim but an eight inch on one side of the neck. I looked at fired cases from another rifle and do not see this dark discoloration.

Is this indicative of a problem with case alignment, headspace, uneven lockup etc?


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## WTM45 (Jan 23, 2007)

Sounds like a chamber that is too big, or a powder that is too slow.  What are your case measurements after firing?
Are they within spec?  Does this powder show up on all loads fired regardless of powder used in the load?


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## hunterb (Jan 23, 2007)

I just bought & zeroed a new M77 .308.....used Federal 150 grain Nosler Partition...about 31.00 a box ....I did shoot a 100 yd 1" group


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## Buzz (Jan 23, 2007)

There are no headspace or bolt lockup problems inherent with with M77.   That's not to say there have never been guns with headspace issues let out the door but that's a stretch to say they are prone to such problems.    Seeing as excessive headspace would create a safety issue, nobody is going to produce a product that is prone to such condition.  One of the problems with the Ruger M77 has been that their barrels were once of  questionable quality - but that has nothing to do with headspace.

Sometimes the soot around the neck as you describe is caused by loads that do not develop enough pressure to fully expand the case neck and some of the expanding gases get by the neck before it blows out fully against the chamber walls.


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## Wild Turkey (Jan 23, 2007)

You may be setting the bullet too deep and it isnt right up against the riffling.
Seat the bullet partially, put the bullet in the gun and seat the bullet with the bolt. pull it out measure it and seat the others in your press to match.
Also get your trigger worked on the m77 has a horrible trigger pull.
I use imr 4831 powder for mine. But if I told you the load id have to kill you.


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## WTM45 (Jan 23, 2007)

Wild Turkey said:


> You may be setting the bullet too deep and it isnt right up against the riffling.
> Seat the bullet partially, put the bullet in the gun and seat the bullet with the bolt. pull it out measure it and seat the others in your press to match.
> Also get your trigger worked on the m77 has a horrible trigger pull.
> I use imr 4831 powder for mine. But if I told you the load id have to kill you.



That's not the recommended way to set your loads for OAL.  It is not advised.
Not every M77 has the need for trigger adjustment.
If you are using 4831 in .308 loads, well.......


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## Buzz (Jan 23, 2007)

Betcha that one makes a nice FIREBALL in low light.


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## duckbill (Jan 23, 2007)

Varget is a good powder in the 308 especially over the 165gr pills.

Are you using virgin brass?  Fireformed brass from your chamber should improve your accuracy.  Keep the brass from each rifle seperated for this purpose.


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## Larry Rooks (Jan 23, 2007)

If it were a headspacing issue, you should have cases cracking on you and they would be black on back towards the rim.  I have had two guns in my life that the headspacing was bad on and on both, the cases cracked on the neck and shoulder and were black well back on the cases.  Check your loading data good, and powder used
to make sure you are getting enough pressure.  Three
powders that work great in the 308 are Varget, Win 748 and H322.  DO not set your OAL with the bullet touching
the grooves but maybe one to two thousanths OFF


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## Buzz (Jan 23, 2007)

This is what cases will look like if your rifle has excessive headspace and you don't adjust your reloading dies accordingly.


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## Oldstick (Jan 23, 2007)

Thanks guys.  I haven't shot any handloads in it yet.  So my next move will most likely be to start down that road and maybe try a few of the "premium" ammo selections.


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## WTM45 (Jan 23, 2007)

A dirty barrel can do weird things to the necks too.  A little discoloration or soot is not uncommon from a severly fouled bore.  Give it a once-over before the next string, especially the throat and leade area of the chamber.


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## caver101 (Jan 30, 2007)

Do you have a way to post a pic of the case in question?


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## caver101 (Jan 30, 2007)

7x57 said:


> This is what cases will look like if your rifle has excessive headspace and you don't adjust your reloading dies accordingly.




That looks like a gore cut in the camber by a metal flake getting caught in the reamer during chambering. I had a rifle built that had that happen (I have a pile of brass that looks just the same). Mine was about half way down the case.


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## Buzz (Jan 30, 2007)

That was a headspacing issue a fellow got while fireforming a standard case in an AI chamber.   No doubt a metal flake can cause problems, but excessive headspace can certainly cause cases to partially or fully separate when reloaded.   

Here is another example of some cases that are showing tell tale signs of excessive headspace after two firings in aRemington 788.  One more firing and these cases would have been split partially or fully which isn't a pretty thing.   I cut one in two and the case walls were quite thin where the yellow ring is.


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## caver101 (Jan 30, 2007)

Yea, those look like the norm. 

Just had never seen one like the first one due to headspace issues, looked like a chamber problem from the pic.


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