Gentlemen,



I recently acquired a recent production M70 supergrade in 300 win mag. This rifle has a most unusual problem, at least to me.

The rifle cycles smoothly, and readily chambers all factory loads I have tried. However, after firing the rifle, initially it absolutely refuses to allow the bolt to open. The bolt handle lifts readily, not like a load developing excessive pressure. It is almost like the bolt is not fully rotating, and the bolt lugs are still engaged. There is simply no way to retract the bolt. After about 30 seconds, or 4-5 tries lifting the bolt handle, closing it again and trying to pull the bolt back, suddenly the bolt opens normally. Of course at this point I'm pulling on the bolt so hard, never knowing when it will eventually open, that I usually eject the case about 20 yards. Effectively I have a single shot m70, that is driving me mad with frustration. The only saving grace is that it is shooting very, very accurately.



It seems to me there are only two possible things happening. In fact, the bolt may not be fully rotating, and the bolt lugs are still engaged. I have lifted the bolt handle pretty vigorously to try and ensure adequate rotation with out success.



Alternately, I wonder if the chamber is so rough or improperly dimensioned that the case is binding in the chamber. Eventually, the case cools down and "shrinks", so after a bit of a struggle, the case finally releases. I've detected a very small bright spot on all cases just in front of the belt, but nothing that really seems extraordinary. The case head looks normal, and the primers look normal without pressure signs. These are factory loads from three differnt manufacturers. I've also measured fired cases ahead of the belt at not even .001 inch larger than factory unfired cases, which doesn't seem like anything out of the ordinary.



O.k., I'll just stop my desscription and ask for help.

Any ideas???



Bill

Have you ever tried some Moly lube on your locking lugs? All it takes is just a small dab and work it into locking lug recesses. If that doesn't cure your problem, try a different brand of ammo and see if it still does the same thing. If all else fails, take it to a good gundoc.

I've seen this symptom before, but it may not be due to the same cause.

Lift the bolt slowly the next time this happens and see where the bolt first starts camming on the back of the action. I've seen Wins where it never cams back enough to start the extraction. If that's the case then you have a choice of welding up and grinding down either the extraction ramp on the back of the action or the contacting surface on the root of the bolt handle. Neither is a very attractive alternative, especially on a new rifle.

On a hunting rifle you'd like the camming action to start the extractor pulling on the case rim when the bolt handle is 1/2 the way up.

Good luck,
Don

From your post I assume it is a standard factory production straight out of the box M70? If it is a new rifle, take it back where you bought it and ask for another. Don't waste time with gundocs and experiments this way you will be able to sleep at night and have more time to practice in the day rather then figure out what is wrong with it

Happy hunting!

I shoulda thought of that, it seems to be the easiest solution.

bwanamich,

Yours is probably good advice. I learned long ago that some rifle just aren't worth the trouble of working up a good load, as some will never shoot really well. I should probably apply the same logic here. The one reason I'm putting a bit of extra time into this rifle is that it does shoot extremely well. (I can't decide if this is just because I have to wait a few minutes between every shot! On the other hand, my blood pressure goes up everytime I try to work the bolt, so you might think it would shoot worse.)
If I don't come up with any concrete solutions, the rifle will go back to Winchester.

I'll look into when the camming of the bolt begins. That is something I hadn't considered. Also, I've tried three different brands of factory ammo, as well as some handloads which have worked well in other rifles. It is not the ammo....

Thanks for your suggestions.

Bill

You might consider posting this on the gunsmithing forum. A couple of the best that haunt there don't visit here often.