bolt is gouging my headstamp

[outdooraddict]

i have a ruger m77 mark II in .264.  I got it used from a friend and he bought it new.  I have hunted with it, killed a few animalsetc.  i shoot my own reloads. but i am running into a frequent issue. i can close the bolt all the way no problem but when i go to close the "knob" or the "bolt"  it is very hard to close. after ejecting the shell i notice that i have gouged out a perfect circle on the headstamp.  accuraccy doesnt change between each round "tigh and loose). It is not every piece of ammo either, some chamber perfectly smooth and the bolt closes flawlessly.  any idea where to start. i have trimmed below spec length, and ploished "tumbled" my cases, the cases are clean and the gun is not dirty that i am aware of at least

[Magnum_Willys]

i can close the bolt all the way no problem but when i go to close the "knob" or the "bolt"  it is very hard to close.

Huh?   Bump back couple thou more and try?

[jasnt]

Are you sure your not touching the lande’s.  Sounds like your jamming and getting preasure signs. Those that are hard to chamber. Can you eject the live round and still have marks

[outdooraddict]

so am i understading this right,  when i push the bolt compltely forward, the bolt essentally "grabs the cartrige?  and as i pull the bolt dow to close it, the entire case is spinning because the bolt should have grabbed the headstamp area?  if this is true, then i am spining that bolt against the headstamp causeing a gouge, likely becasue it is to tight in there to spin freely? 

[outdooraddict]

yes it gouges when i chamber the live round, ejecting has never been an issue, it is only in the "closing of the bolt" phase of chambering the round

[jasnt]

Got a pic of the headstamp. Maybe include a close up of the bold head focused on the ejector and pin

[BULLBLASTER]

The Ruger mark ii action uses a claw extractor and a static ejector ( maybe not the right words?) but it isn’t on the bolt, the bolt opens to it and it flings it out.

Something is off with the brass or ammo and it’s too tight.

Can you chamber a piece of brass after prep but before you load it? Does it mark it the same as a loaded round?

[kentrek]

Check your headspacing 

[davef]

Are you letting the bolt pick them up out of the mag box or do you drop on in and close the bolt? Generally on a control round feed it's best to feed from the mag box but could be a mute point. Just a thought

[BigGoonTuna]

check your cases with a comparator.  my guess would be that  you have some that need the shoulder pushed back.  does factory ammo chamber easily?

.264 mags are weird creatures.  i had one(a model 700 from the 60s) that if loading to book OAL, bullets would jam into the rifling about .020

[outdooraddict]

my next step is to buy some factory ammo and chamber those, that will narrow down the problem in my gun versus the case. i did chamber a used, but freshly tumbled and resized case, and it was real hard to close the bolt,  a guy at work said i likely need to aneal the necks, or push the shoulder back. it seems to me the the shoulder is to far forward. do i screw my resizing die in a little further to push the necks back or isit a totally different die?  once the round is fired in my rifle, theoretically it should be "fire formed" to my gun, correct?  so if i switch to just neck resizing then i should be good?

[jasnt]

You want to bump the shoulder back. Just neck sizing is going to make the issue worse.  Just screw your die in a 1/8 turn and size a peace. Then chamber it. Keep doing that till you can chamber easy.  If you bottom out on the shell holder you may need to take a little off the shell holder or order a shorter shell holder.  If you have more than one of the same shell holder it’s a good idea to mark the one you use as they are not all the same dimensions

[BULLBLASTER]

Take the same piece of brass yu just tried, fired tumbled then resized.
It chambers tight? Screw the sizing die in 1/16 of a turn and size it again, is it still tight to chamber? If so screw it in another 1/16 turn and try again. That will bump the shoulder just a bit.
With calipers and a comparator you can measure that shoulder bump. I used to use a piece of pistol brass before I got the comparator set.

[hughjorgan]

my next step is to buy some factory ammo and chamber those, that will narrow down the problem in my gun versus the case. i did chamber a used, but freshly tumbled and resized case, and it was real hard to close the bolt,  a guy at work said i likely need to aneal the necks, or push the shoulder back. it seems to me the the shoulder is to far forward. do i screw my resizing die in a little further to push the necks back or isit a totally different die?  once the round is fired in my rifle, theoretically it should be "fire formed" to my gun, correct?  so if i switch to just neck resizing then i should be good?

How many times have you reloaded and shot the same brass. Have you ever trimmed your brass?

[outdooraddict]

yes i have trimmed them, it is not an issue with overall length. I really think it is the shoulder is just a little to far forward, squishing the cartridge into the chamber, resulting in the bolt spinning around the head stamp instead of the cartridge spinning while the bolt closes, if the shoulder is bumped back a little bit, i am hoping it will fix my problem. i only have about 18-25 pieces of brass, because i got rid of the others that were to tight,  ill start with a box of factory to shoot and then use that brass too, its my hunting gun, so at the rate of the last few years, only about 5-8 shots for the year, including some pre season shots. lol