Sick 742 in 6mm

[fredtay]

New to board. Interesting reading. Got a problem with a 742 in 6mm. It backs primers about 1/2 out on factory ammo only. Reloads do fine (I tend to load a between min and max listed loads). Having trouble finding a gun doctor that will fool with it. It was the last gun her dad gave her before his death. I'm guessing probably less than 300 rounds ran through it.
Other than the above listed concern it definitely shoots good. Would like to have it fixed for her. Any ideas??????

[600RemGuy]

Don't consider your gun sick just yet. Ammo acts different in different guns. Does changing ammo brands make a difference? Your chamber may be tight or long. Your reloads have fire formed to your chamber which is why the problem doesn't show in them. A simple head space check should put your mind at ease and any smith worth their salt can do it for you for 10 or 20 bucks. Lastly, the action may be stiff if it hasn't been use alot or in a while. Some lite compound, removal of the trigger and running the action a few thousand times may smooth things up.

[fredtay]

Rem Guy thanks for the response. The ammo is the same as my wife has been using all along. Just plain ole Federal and Remington. I agree that the head space should not be a big proglem to check but for some reason when you mention 742 everyone shy's away and says buy a new gun it can't be fixed cause there are no parts. I found one gunsmith willing to look at it. He has ahd the gun since November but hasn't "gotten around to it". Also, he died last week so now I'm back to square one. I have no problem just using reloads, but something is making the rifle back out factory primers.

[Bob Smalser]

Generally if there is excessive headspace there will be bright ring of stretch marks around the case just ahead of where it normally expands and obdurates (seals) the bore. That's a fourth to a third of the way north of the rim. Sometimes half way in long cases. Check your fired cases carefully. Ringed cases mean the rifle isn't safe to shoot without repair. If the case splits between the bolt and where on the case it finally obdurates you will get a face full of gas.

Primers backing out is usually caused by loads of too little pressure. The case doesn't expand quickly enough to press the case head against the bolt before the case fully obdurates. The case obdurates with a tad of slack between bolt face and cartridge head, backing out the primer.

In factory loads, too little pressure is unlikely. As is excessive headspace in a tried and true rifle unless the bolt or barrel has been changed, and I don't think many of these had barrel changes.

The last possibility I can think of is the rifle is cycling after the case fully obdurates, but before chamber pressure is completely reduced. The bolt face moves with the case fully sealed but the remaining chamber pressure backs out the primer. After you check all those fired cased and determine the rifle is safe to shoot, change the recoil spring to new or as close as you can come to it and see if there's a change. Sometime during its life someone may even have cut that spring for more reliable functioning with light loads.

[fredtay]

Bob thanks for the reply. I finally found time to fool with the rifle some more. Shot some factory Federals and a few reloads. There is none of the markings, you mentioned, on any of the cases that I could tell. Only marks I could find was a bright ring where the case starts to neck down. I'm assuming this is from the contact with the end of the chamber and the start of the barrel. The primers are backing out so slight that if I were not paying attention I could not tell it.
I'm not an automatic rifle person (Don't dislike them, just don't have anything but a few military types) so I'm wondering if I may not be cleaning it like/ as well as I should.

[geezer in NH]

Slight factory primer back out, Forget abotit IMHO