Headspace

[ctgodog]

What is headspace?,....what does it do?, is it adjustable,? and if so, how do you adjust it?

This is my problem.....My recently acquired Model 81 35Rem doesn't always cock the hammer when jacking a cartridge into the chamber....I can't pull the trigger...when I release the bolt with the bolt release lever, and it slams closed on a chambered round, it fires the round. When I get a round chambered correctly, the trigger pull is very light. Firing a magazine load functions correctly, and ejects perfectly.... Now that I have rotated the scope 90 degrees to get the scope adjustment knobs out of the way of the ejection process.

My second question, is this...my scope has a vertical post, and a horizontal line....by rotating the scope 90 degrees, to get the adjustment knob out of the way of the ejection function, the horizontal line becomes the vertical line, and the post becomes the horizontal .....Can this arrangement be sighted in with any accuracy??? Or, do i need a different scope???

Any and all help will be appreciated!!!

Clint

[DWalt]

I don't think you have a headspace problem. Headspace is merely a measure of how tightly or loosely a cartridge fits into the chamber, and for most guns it is not something that is easily adjusted (and very seldom needs to be).

I believe you have some problem with your trigger group, tough to say just what the problem is from long distance - but it ain't headspace.

You can rotate your scope 90 degrees with no problem.

[Sarge756]

Clint,
The scope question first. The post and crosshair won`t work with the turrents rotated to clear the ejection port. You`ll have to get another scope with regular or duplex reticle. This question was covered in a couple posts under "scopes for the 8/81" recently.
Headspace, is the measurment of the portion of the chamber that stops the forward movement of the cartridge to the face of the bolt.In the case of the Mod 8 and other firearms chambered for rimless bottleneck cartridges the forward motion is stopped by the shoulder of the cartridge. Rimmed cartridges like a 45-70,303 British and the like are headspaced from the rim to the bolt face.Headspace problems usually show up as ruptured /split cases and protruding primers or in rounds being hard to chamber.
Your problem being due to headspace would not seem likely.Certainly not the slamfire situation you described.That and the light strike of the firing pin would seem to dictate a sticking or fouled firing pin. Not a good situation.Slamfires give me the shivers. If you havn`t , a complete bolt disassembly, cleaning and inspection or in order.

[kenhwind]

Sounds to me like maybe a worn trigger or sear hook. Maybe someone tried to improve the trigger pull.

[ctgodog]

Well, I have solved the scope problem by moving the scope forward in the mounts, so that the scope adjustment knobs are forward of the front mount. It seems to be a better position for a full view through the scope, and it gets the adjustment knobs out of the way of the ejection port.. I don't have to hunt for the right distance of eye relief from the rear of the scope. It seems to come up more naturally for a full field of view. Probably where it was supposed to be in the first place. I'm starting to think the the typical gun store owners don't know beans from rocks.

I will disassemble the bolt and clean it, and check out the trigger group....not that I would probably know if it was bad by looking at it!!! I would go "Yep, that's the trigger,"....I wouldn't know a good one from a bad one!!! But, I will try the cleaning first.

Thanks for all your help.

Clint

[Sarge756]

Glad you solved the scope problem. Would be a shame not to use a post reticle(My favorite).What scope is it? Yes you are correct most counter jockeys at the gunstores are less than able to help with the old stuff we deal with.
If you havn`t, review the post on Mod 8 disassembly by Jonbegood .The link there has some good close up photos of all the innards and you should be able to compare and spot a problem if there is one. Good luck. Joe

[ctgodog]

It is a 1" Weaver, 10" long. It is mounted with Weaver scope rings, and a two thumb screw detachable Weaver side mount.It is actually a very nice setup. It is clean, simple, and low profile.

Clint

[ctgodog]

Update on the 35 Rem slamfire/non cocking situation.....I took the rifle apart, cleaned the bolt assembly, and checked out the trigger group assembly. Cocking and releasing the trigger group assembly several times by hand, indicated to me that the hammer sear and the trigger sear (if that is the right terminology) were not hooking up properly (barely catching a hold of each other). It appeared that someone had done some trigger work on it and the two parts were not fully engaging. So I decided that the remedy would be to file the backside of the trigger, so that it would go back farther, and engage more fully with the hammer. First try improved the situation, about 50%, so I took a little more off, and checked the engagement,and it was an improvement. Took a few more strokes with the file and got it to where I thought it was right. Reassembled the rifle, and took it out for a test firing today.

NO SLAMFIRE, PROPER COCKING FUNCTION, AND THE SAFETY OPERATED PROPERLY!!!!!!! YEEEAAAH!!!!!!!

I am so happy that I can hardly spit!!!! But I did!!! I spit a whole box of ammo through her and sighted it in, both with the open sights and the scope. Now she is fully operational, and ready to go................

Thanks for every ones help in solving my little problem............

Clint

[Sarge756]

That`s great news Clint. Looks like Ken hit the nail on the head with this one. Now you have the satisfaction that you did it yourself with a little help from your friends. Were you able to get any decent groups with the scope setup and all those rounds down range?
Joe

[DWalt]

One thing you might want to try for safety's sake is to bounce the butt on a wooden surface firmly, but not enough to damage anything, with the hammer cocked and the safety off. Idea is to check that impact won't jar the sear engagement loose, resulting in accidental firing if the rifle is dropped.

I don't know about the Remington M8/81, but some trigger mechanisms have hardened sear engagement surfaces, and if you cut through the hardened surface skin, rapid wear can occur. You have to be careful not to change the angles of the engagement surfaces. An abrasive stone (fairly fine) is usually the preferred implement for doing any sear surface smoothing.

[ctgodog]

Once I got the scope on the paper and zeroed in, the grouping was 2-3" , and I am OK with that. It will hit the kill zone!!! I am not really looking for a competition grouping. Just get the meat on the ground.... The open sights were right on target with even a little tighter grouping.

Clint

[imfuncity]

Way-cool with the file. Spitting lead - definitely minute of deer! Great job.