Rossi 92 headspace

[Bushrat]

I have a brand new Rossi 92, 44mag, that is causing case separation about one half inch from the rim. The bolt will close on a .016 shim but not on .020 shim. Is that excessive head space, and in turn causing the separation?

[Der Gebirgsjager]

The rim thickness spec. for a .44 Mag. is .06". That is considerably more than your shim thicknesses, so given the information you have provided I would say that headspace is unlikely to be the culprit. I'd like a detailed description of your shims and how they were used. I'd also like to know about your ammo -- factory loads? Reloads? New brass? Old brass? Yours is the second recent post about case separations in the Rossi R-92 .44 Mag. I have one and have experienced no problems. I'm using reloads, but started with new Starline brass. One poster stated that he could observe a ring in his chamber. What does your carbine's chamber look like? Are your loads excessively hot? There is a certain "springiness" to lever actions, and a hot load might be enough to develop headspace issues with a carbine that had marginally good headspace. We'll probably be better able to offer conjecture about your problem with more information.

[Jedman]

Do you mean it will close with a .016 shim along with the brass casing. If so that is excessive for any gun.

Jedman

[Bushrat]

I was one of the previous posts, the ring in the chamber was caused by several case ruptures. I cut round shims from a pop can each .004 thick one ar a time placed them on the back of a case and closed the bolt. I could close the bolt on four but not on five. This tells me I have more than .016 of headspace above what is required to chamber the round. I think that is too much, loads were mild you might not get separation with factory loads but I would hesitate to use those cases again if that headspace is excessive.

[tja6435]

This is interesting, I’ll follow this thread for my education

[M-Tecs]

"Head Space" on a cylindrical case with a rim will have no bearing on case separation. It is not like a bottle neck rifle case. The bottle neck is captured between the shoulder & the bolt face, this keeps the case from stretching. On the 44 Mag the pressure is captured between the case head & the bullet so if is going to stretch & separate it will even if the rim is clamped tight to the bolt face. You need to look for other problems. If the cases are bulged your chamber is out of spec. If ammo is factory new casings try a different lot #. If these are reloads brass may be worn out. If gun is new call dealer or Rossi customer service. Make casting of the chamber.

Troll alert: I know that bottle necked rimmed rifle cartridges as well as belted magnums "head space" off the rim & belt BUT if the bolt face to shoulder distance is excessive they will separate. Been there done that have the Tee shirt.


Case head separation is caused by the same thing regardless of the method of actual headspacing. The firing pin pushes the case forward and the thinner part of the case expands to seal the chamber. As the pressure increase the case head moves back to the breech or bolt face and since the thinner mouth portion will have more friction due to its thinner walls the case stretches.

For any bottlenecked cases that have rims or belts best practice is to set you dies for your shoulder clearance same as rimless bottleneck cases.

[John Taylor]

Head space should be .002- .004". On low pressure cartridges the primer will back out. Depending on wall thickness of the brass the pressure can very on which loads will have head separation or not. Cartridges like the 30-30 ( 42,000 psi ) will usually back the primer out. The 44 mag at 36,000 has thinner brass and can separate the head. I had a 454 with about .008" headspace that separated a few weeks back. I usually use masking tape to check head space on old guns, had a 94 a few years back that had .025" head space and was still being used. It would back the primers out and thats how the head space was measured.

[Paul24]

M-Tecs, do you really believe that .016 inch clearance in the head space on 44 magnum will cause case separation?

[M-Tecs]

M-Tecs, do you really believe that .016 inch clearance in the head space on 44 magnum will cause case separation?

On the first firing of the brass no but with repeated loadings yes. That being said I have never worked on a 44 magnum with this issue. I have set the barrels back a Martini Cadet in .38 special, a 45 Colt in a Winchester 94 and a couple of 45-70's that separated cases due to headspace issues.

[Der Gebirgsjager]

Your rifle needs to go back to the factory, or to a warranty repair station.

[LAGS]

I had a Mosin Nagant made in 1896 that had a headspace issue.
There was .012" clearance between the case head and the bolt face.
Sometimes they would split the cases when using steel cased ammo.
But the Brass cases stretched.
I would just neck size them, ( Norma cases ) and reload them.
I was able to get over 20 reloads out of the once fired cases before the necks started to crack.
Finally I decided to Silver Solder a .010" Feeler gauge Shim onto the bolt face to take up the extra headspace since I could not find a bolt head replacement that closed up the headspace.
And no gunsmiths in my area wanted to remove the barrel and set the barrel back because the chamber reamers were not available at that time.
That was in the early '70's and I hadn't bought a lathe yet.
I sold that rifle to a friend, who sold it to a friend, and he still has it and is shooting it to this day with Steel Cased ammo with no problems.
Rimmed cases are way more forgiving than Straight Rimless bottleneck calibers.
Both owners of the rifle were Fully aware of the modifications that I had made to the bolt face and the possible headspace issues.
They didn't care because at that time, the Nagant was not a popular shooter.
I know the current owner has shot up an entire 440 round Spam Can of surplus ammo with no issues.

[M-Tecs]

No clue as to steel handles excessive headspace. With brass cases as long as the case head is held against the bolt or breech face the fireforming process does not show any internal head separation signs when you are blowing the shoulder forward for wildcats. Best is to form a false shoulder but jamming the bullet into the lands works well also.

A while back a buddy inherited a 60's vintage custom rifle in 257 Robert Ackley Improved. The woodwork and blueing was as nice as I have ever seen. The chamber not so much. It was cut .030" deep. I agreed to set the barrel back, however, after seeing that the blueing was flatout gorgeous I was worried about damaging the finish. Showed him how to properly fireform the brass using jammed bullets and set his die for a .002" shoulder setback. Not truly an AI anymore but treated as a wildcat it works well. He hasn't had an issues with it in 15 years. Case life went from 2 or 3 loadings to over 20.

[bmortell]

I was the one with an actual step or ring of sorts in the 44 rifle chamber that was tearing my cases in half, I lapped it with sandpaper. I don't know how long my cases will last now but it was about a year ago I did that and ive still never seen any type of damage on cases

[onelight]

I would fire a few factory loads through the rifle and if needed section the cases and look for a thin spot to eliminate hand loads from the problem and include them when returning the rifle .
Or if you or a gun smith determines it has a headspace problem and has not been modified in a way that could cause the problem I would return it and let them fix it.
It’s a new rifle give them the opportunity to make it right.

[Jedman]

On most centerfire firearms a simple test for headspace is to take a sized and primed casing , not a loaded cartridge and fire it in your gun. When you get the brass out of the gun look at the primer if your gun has excessive headspace you will see the primer has backed out and no longer flush or below flush to the back of the brass as before firing.
There are some firearms that have a extractor or ejector that can hold the cartridge tight enough to the bolt face that this test may not show the correct issue but for most guns this test will show you if you have a headspace problem, bottle necked or strait walled both.

Jedman

[justashooter]

julian hatcher experimented with headspace in 1919 belt-fed autos chambered in 30-06 and determined that case head separation begins at 15 thou and is consistent at 25 thou in that combination.

he was cheif ordnance officer at the time.

[onelight]

On most centerfire firearms a simple test for headspace is to take a sized and primed casing , not a loaded cartridge and fire it in your gun. When you get the brass out of the gun look at the primer if your gun has excessive headspace you will see the primer has backed out and no longer flush or below flush to the back of the brass as before firing.
There are some firearms that have a extractor or ejector that can hold the cartridge tight enough to the bolt face that this test may not show the correct issue but for most guns this test will show you if you have a headspace problem, bottle necked or strait walled both.

Jedman

I bet most factory guns and cases would let the primer back out to some extent , how much is to much?

[Jedman]

If you can feel the primer above the surface of the casing it's probably at least .005 and that is probably OK but if it's .010 or more it's too much.

Jedman

[Bushrat]

I took the 92 back to the range, fired 10 rounds, they functioned great but I could see a faint ring on one and could feel it from the inside. One other had a distinct ring you could feel with a thumb nail on the outside, and with a wire on the inside. I now have no doubt excessive headspace is the problem, and will send it back.

[onelight]

I took the 92 back to the range, fired 10 rounds, they functioned great but I could see a faint ring on one and could feel it from the inside. One other had a distinct ring you could feel with a thumb nail on the outside, and with a wire on the inside. I now have no doubt excessive headspace is the problem, and will send it back.
I hope they get it fixed for you.
I have had to return several new guns back for repair mostly Rugers also Springfield ,Glock , Kel-tec but I keep buying cause I like um all :p, but have found it wise to run a few boxes of ammo through any new gun before sights or any other kind of upgrade.

[indian joe]

"Head Space" on a cylindrical case with a rim will have no bearing on case separation. It is not like a bottle neck rifle case. The bottle neck is captured between the shoulder & the bolt face, this keeps the case from stretching. On the 44 Mag the pressure is captured between the case head & the bullet so if is going to stretch & separate it will even if the rim is clamped tight to the bolt face. You need to look for other problems. If the cases are bulged your chamber is out of spec. If ammo is factory new casings try a different lot #. If these are reloads brass may be worn out. If gun is new call dealer or Rossi customer service. Make casting of the chamber.

Troll alert: I know that bottle necked rimmed rifle cartridges as well as belted magnums "head space" off the rim & belt BUT if the bolt face to shoulder distance is excessive they will separate. Been there done that have the Tee shirt.

Methinks you got yr tee shirt on back to the front
Excessive headspace .......
1) primer strike drives case forward
2) case expands up front and the case wall grips the chamber
3) pressure drives the case base backwards against the bolt face
4) case wall is still glued to chamber wall up front
5) case stretches and thins where the wall joins the solid head
happens this way in any case where there is excessive headspace and enough chamber pressure/soft enough brass to expand the thinner part of the case to grip the chamber wall - happens same with weak (springy) actions and heavy loads too
Suggest you remove tee shirt and put it on right way round.

[M-Tecs]

M-Tecs, do you really believe that .016 inch clearance in the head space on 44 magnum will cause case separation?

Per the OP's actual experience


I took the 92 back to the range, fired 10 rounds, they functioned great but I could see a faint ring on one and could feel it from the inside. One other had a distinct ring you could feel with a thumb nail on the outside, and with a wire on the inside. I now have no doubt excessive headspace is the problem, and will send it back.

[yeahbub]

That is excessive headspace. I knew a fellow who had a '92 in .44-40 and the cases stretched .008 with each firing. They were good for one, maybe two reloads before they would separate. A temporary fix he used was to lubricate the outside of the cases with some soft, waxy boolit lube or case sizing lube. They were all in the mag tube and wouldn't get dirty anyway. When they were fired, the case will slide back to the bolt face without stretching and case life was almost indefinite. Send it back while it's under warranty.

[Bushrat]

Thanks all, rifle going back next week. Rossi waived the shipping fee, which they didn’t have to.

[yeahbub]

Good move. Lubing cases works well when necessary, but long term, it's unpleasant tedium, especially on a new rifle that should never have shipped that way.

[justashooter]

cheap field test is to put two thicknesses of scotch tape on the base of a factory load(unfired), amd try to chamber. more than 3 thicknesses is excess, as scotch tape runs about 2 thousandths, and you want 4-6 in a field gun, and 2-4 in a target gun...