Need help: Lever opening on firing BB94

[C. Cash]

Thought I would pick ya'll brains on what is happening with my Big Bore 94 in 356 Win. as it really has me scratching my head. I have had this gun since I bought in new in 1992....put perhaps 60 factory rounds through it initially and over the past 10 years have shot probably 700 cast rounds through it . I have noticed over this past year that the lever seems to come down at the shot and the round is partially extracted. The reason I kept on shooting when this was happening is that I was initially convinced that it was just the recoil of the gun with my hand in the lever causing it to happen. I shoot cast loads that are nearer starting than max...feel little need to go beyond 2000-2100 fps with the cast bullet, but these are not really "reduced" loads that one often sees with cast. On my last range session, I distinctively felt the lever/bolt open at the shot and it sent chills up my spine so I have definitely ceased shooting until I figure out the problem. Some facts:

-I am loading 41.0 gr. of H4895 behind a RCBS 200 gr. FNGC sized .359 Other loads in which this happened, but which I had thought was just recoil, was 42.0 gr. of IMR 4320 with Beartooth 210 gr. and a short session with H322 with that same bullet. Again, these were starting or below starting for jacketed bullets in the Speer manual, and these are cast bullets which should offer even less pressure.

-I shot some factory 250's here recently which I had had since 1992. They did not seem to open the action though they were definitely stout loads. The primers appeared slightly cratered but again did not seem to open the action at all.

-Cases look normal...no line indicating a head seperation, primers look normal.

Could it be lube on the case, lube on the back of the bolt/locking lug, headspace, "springy" action, etc? Also thought of the case not expanding out to grip the wall of the barrel and creating alot of breech thrust....but all just guesses. It seems it should really be spanking my hand if was anything serious, but it just opens about an ince. Seems to open with the slower powders but perhaps a coincidence. I would appreciate any input.

[J Miller]

C.Cash,

The first thing I would do is check the friction stud at the rear end of the link. That is what holds the link closed. It should move in and out freely, and it should positively lock the link closed.
I've had them come from the factory so loosely fitted the lever/link would fall open if you lightly shook the rifle.

After that I'm not sure.

Joe

[Griff]

I've generally found this to be a headspace problem. Not incurable, but you do need to rule out the headspace issue before going further. One other possibility is that the bolt is loose in the rails and is slightly riding up on the locking lug, forcing it down upon recoil and thus forcing the lever down.
While I don't disagree with Joe about the friction stud on the link; it should definitely hold the lever up when in battery, but... it shouldn't be expected to hold the lever if movement of other parts are forcing the locking lug down. Check to see if the locking lug is being pushed down, it should remain level with the top of the receiver after firing.

[C. Cash]

Thank you Gents for a good place to start. I will make a thorough inspection tonight of these parts and areas and see whats shakin'....literally!

[O.S.O.K.]

The 356 Win headspaces on the rim. I think I would take this to a knowldegeble smith to take a look...

[Hagler]

Chris,

My B92, with a Rossi large loop lever, does not have a friction stud. The lever did not come with one, and the Browning stud does not fit it. I have had zero problems with the lever flying open. My rifle is the .44 Magnum flavor. I realize that the 94's lockup is not the same as the 92's lockup, but my experience, with Magnum rounds, is that the stud is not needed. ...and you got that there new-fangled .356, too.

Shawn

[Bruce]

Sounds like the locking lug is not doing its job. It could be worn, undersized or something could be keeping it from coming up far enough. The rails on the bolt may be a factor as already pointed out. Close the lever and see if you can use "reasonable" pressure to push back on the bolt and have it over ride the lug. If it is worn or undersized, you can get a oversized one - I just can't remember where at this time.

[C. Cash]

Well I've played with the parts and eye balled everything and nothing seems mechanically amiss. I am leaning towards the headspace thing too. It does have a decent gap between the bolt face and the barrel, but I have just never looked that close so not sure what normal is. I have heard that you can tape a piece of paper to the cartridge rim face to check for headspace? I think I will try this tonight. This is kind of a bummer as this has been my go to rifle for a good number of years and is my Elk rifle for this fall. Gonna have to get this fixed quick! Thanks a bunch fellas!

[Griff]

Use the same "tape" you'd use for checking engine main or rod bearing clearances. Avail at most hotrod shops. Like: Plastigage.

[Tycer]

Use the same "tape" you'd use for checking engine main or rod bearing clearances. Avail at most hotrod shops. Like: Plastigage.

Yep, that's the stuff. Lay a strip on the back of the case head and close the bolt. Measure the width of the smushed plastic on the paper the plastigage came on and voila! Try to run the plastigage where there is no headstamp or fill the headstamp with epoxy or lead.

[C. Cash]

Thanks gents!

[Nath]

Now just hang on dudes! Now this is just my opinion but I see no issue with head space here dudes, not yet any ways.
What I'm getting from this detailed report is brass not gripping the chamber walls.
Cast loads are lower in pressure and lubed! If the cases where gripping the chamber and a head space issue was there a ring would of appeard as the rim travelled rear ward freely.
Also if complete lock up failure was happening it would not just open partially. Mr Cash states that factory was fine.
Please try degreasing the chamber and ammo and try again.
Also make sure the sizing die is sizing enough, I thought I was being clever just neck sizing untill I found out I was slowly jacking the bolt back untill it would not close over a few reloads!

I recently deduced that my 94 will shoot very badly with any form of lube in the necks or on the case's, it may just be a case of the guns action's harmonics being upset from internal goings on.

Nath.

[C. Cash]

Good to hear Nath! Your hypothesis is in equal running here, but it for sure won't hurt to get the headspace checked and then if OK I will start playing with what I'm doing with the cast loads. With the recoil and blast of the 356 Win., the thought that ones loads are not powerful enough to expand against the chamber walls does not immediately come to mind , but it is sure possible in retrospect. I'm getting very inconsistant accuracy as well, which may be tied to whats going on here as you have suggested. Many thanks and I'll let you fellas know what I find out.

[J Miller]

Use the same "tape" you'd use for checking engine main or rod bearing clearances. Avail at most hotrod shops. Like: Plastigage.

I should try that on my No4 Mk1* and see what I have.

Joe

[1886]

If I am understanding your concerns correctly, I have experienced the same issue as you but with a Marlin 1895 .450. It was with very stout loads and it was nothing more than the interaction of the gun in recoil and my right hand. I am a right handed shot. Recoil impulse will do funny things to the lever in a levergun. If your gun never had head space issues what makes you think that 700 moderately heavy loads would cause increased head space? Head space can be easily checked with scotch tape placed on the case rim. Put the tape in increasing layers on top of the rim, trim to match the rim, chamber the empty case with the tape applied until you feel resistance upon final closing of the bolt. Remove the tape and measure the thickness. This will be an accurate representation of your rifle's head space. I bet it is between .004-.010". If so perfectly normal. Also you can check for case head separation with a paper clip bent at a 90 degree angle to form a feeler of sorts. Insert the bent portion of the paper clip into a case that has been reloaded a couple of times far enough to reach to the case head and scrape the side of the case. Is the paper clip catching any groove in the case wall? If so you are experiencing a case head about to separate. This is a good sign of head space issues. This test combined with the scotch tape test is a good measure of any potential head space problems. You could of course buy go no go gauges as well but they are a little pricey or you could take it to a smith. The methods I described to you are methods taught to me. They are reliable and easy to use. Let us know. 1886.

[C. Cash]

Hey 1886. It's possible.....that's what I have felt it was over this past year, and the action has gotten very slick with use, which would help the lever pull the bolt out of battery. But this last time I gave the lever a death grip as I squeezed it shut, and I seemed to distinctly feel it open on the shot. It didn't slap my hand as Slim Iorg has described some of his hot 307 loads....just seemed to open forcefully but was not painful to my hand. I will see if I can feel anything inside the fired case. I've come to think that a combo of things may be happening here.....cases not expanding out to grip the chamber wall, slick cases and alot of breech thrust slamming all the energy back into the bolt and forcing the locking bolt down. This breech thrust may or may not have caused headspace issues by now...hope not. These are just the guesses of an arm chair gun expert By coincidence I did put a piece of tape on the end of a sized case and closed the action just to see what would happen...no resistance but I have not tried 2 pieces yet. Not scientific I guess as my dial caliper will probably not tell me anything with any certainty. I might get a freebie check with a no guage with my local gunsmith as he is usually happy to do something simple for me to get me out his door....without having to get involved in one of my gun projects Thanks too all for your ideas. You guys are the best.

[Nath]

Just try removing the lube for now friend, the cases will be expanding enough to grip. Why I say this is that when a gun is proofed it is done to twice, once to test the barrel and then to test the action. To test the action the proof load cartridge is lubed so it does not grip the chamber and hence all the thrust is against the lock up/mechanism.
If you been getting poor results latly ( which sounds familiar to me) I'll put a hundred bucks down on it (not really ).

Nath.

[C. Cash]

Will do Nath....already have a batch of rounds which I have degreased and will try. For the sake of confidence, I'm just gonna have to get an accurate measure of the headspace. It would ease my mind as I'm pulling the trigger on this beastie and may improve my shooting. Also, I only have one peeper left so I have to take a little extra insurance! Now to call around and see if someone can do a quick check for me and then it's off to the range. I think you have hit upon my accuracy issue with the lubed cases for sure, for reasons I won't bore you with. You may also right about the headspace being a non-issue, but just to be sure....., will try for plasti tape as Griff suggested fommorow or see if my gunsmith has the correct gauge if I can't find it. Thanks my friend, and thanks to all.

[mav]

C. Cash,
do you use Ulmer's? I've been well satisfied with his service (in my limited experience). I'm not familiar with anyone else near Happy Valley. Good luck with your rifle.

[C. Cash]

C. Cash,
do you use Ulmer's? I've been well satisfied with his service (in my limited experience). I'm not familiar with anyone else near Happy Valley. Good luck with your rifle.

Hey Mav,

Yes...I have used Ted Ulmer exclusively here. He is a good fellow and I too have been very satisfied. He mainly does high dollar stuff but every once in a while I can convince him to do something for me .

I used the Plasti Guage "tape" which I got at the local automotive store....more like a small little string that gets mashed, and it reads about .0045-.005 so it looks like I'm okay with headspace. Now to give the degreased cases a try(Thanks Nath!). Should be good to go with this and I'm hoping my groups tighten back up as well. If my cases were looking bad in any way, I'd have reservations about continuing but they have always looked normal. May sound like a broken record but will say AGAIN thank you all as your willingness to help has meant alot. I hope to have a range report up in the next couple of days.

[C. Cash]

Problem solved! Nath seems to have nailed it pretty well. I cleaned my cases with alcohol to get the resizing lube off and not a hint of feeling the lever come down. At 70 yards my groups were OK but need to keep shooting to tighten things up. Wahoooooo! I'm back in business.

[mav]

I'm glad things worked out for you. Is Scotia reopened?

[RSY]

Looks like you missed an easy $100, Nath.

Scott

[Griff]

Glad to hear it wasn't a headspace issue. Wish mine hadn't been; took a while to find the right sized locking lug.

[Tycer]

Glad to hear it wasn't a headspace issue. Wish mine hadn't been; took a while to find the right sized locking lug.

Could a locking lug be built up?

Glad it's fixed Chris.

BTW Nancy calls me "husband". She's the only person I use MSN for IMs.

[C. Cash]

Thank you fellas.

Mav...yes,it FINALLY reopened. I made 6 failed trips out there before they finally opened it. The road has been repaired somewhat as well so you don't have to go 3 mph

[C. Cash]

Glad to hear it wasn't a headspace issue. Wish mine hadn't been; took a while to find the right sized locking lug.

Could a locking lug be built up?

Glad it's fixed Chris.

BTW Nancy calls me "husband". She's the only person I use MSN for IMs.

Aha! Thanks for letting me know that Tycer....I thought someone was starting to take a shine to me in the wrong way!

[Nath]

Check the writing on the card. The right targ is a Speer 110grn load with the lube removed. 30/30.


Nath.

[C. Cash]

Looks like I'm going to start degreasing the inside of the case necks as well! It's funny that I never thought case lube could have such a dramatic effect on things. Hopefully get some more rounds downrange next week that are completely degreased. I've gotten .75" groups with my RCBS bullet so I know the accuracy potential is there. Light seems to play havoc with my sight picture much of the time, and the neon orange target spots on a white background are no longer gonna be used as the eyes tire easily. I am also learning the ins and outs of shooting off cross sticks, standing. Takes nearly all the bite out of recoil, which is nice.

[Nath]

Note that degreasing inside the neck will only help with jacketed bullets.
Good luck and keep us posted

Nath.

[Nath]

No, no, I'm wrong to say that as I don't actually know that, I'm assuming!

Nath

[RSY]

Instead of non-lubed necks, I imagine using motor mica would give the same results. I have one of the Forster kits, and love it.

Scott