Bumping case shoulders and head space questions for lever guns.

[Tripplebeards]

I pulled out my marlin 336 chambered in 35 Remington out of the back of my safe about a month ago so I could start experimenting with cast. I used a fired case and slid one of my group buy cast hp boolots in it. I candled it and closed the action. I did this several times. My OAL was 2.464” if I remember correctly. I ended up loading it at 2.415”. My bore slugged at .357” and I sized them at .3595”. When I chamber my 2.415” loaded round it had micro groove rifling marks engraved on my boolit. I posted about this and most said that is perfectly fine and more than likely will aid in making my my loads more accurate. Well it sure did. The first trip out my best group was MOA at 100 yards.



The second trip out I lightened the Trigger first From 5 pounds to 2 1/4 pounds and re tested my Varget load that shot 1” at 100 yards. The first three shot group all went on one hole. I had another powder shoot a .7” group at 100 yards as well.





So things are looking good accuracy wise! On the down side I had a few rounds that when I closed my lever it spring back open just a hair..I would say a quarter inch or more. It felt spongy and did not want to lock into place. This only happened with a couple rounds. Also when this happened the trigger would not set. If I queezed the lever flush it would fire...or if I opened the lever about 2”/3” and slammed it back home It would then Close flush and fire.

So these are some of the things I though might have been the culprits...

I had a couple primers that weren’t seated flush. Maybe two or three out of 60 plus rounds I fired. I had a FTF with these and then if I cocked the hammer again and pulled the trigger and all three shells fired. When I inspected them all three primers were sticking out and not flush. I was using Remington cases I bough new and have maybe been shot 3 to 4 times. They were also all annealed a few months ago. I didn’t ’t use my rcbs hand primer for these few test rounds and used my rock chucker to install the primers. Hand priming will be done from now on. I also noticed that when I adjusted my trigger and tested it by bouncing the buttstock off the floor and with a rubber mallet the lever kept opening. The gun was made in 1970 so figured the plunger spring was getting weak. Yesterday I removed the lever plunger and spring. I stoned my plunger to more of a sharp angle and stretched my spring. I reassembled and tested. The lever locks up firmly and does not open now. I also wanted to inspect my firing pin. I removed, cleaned and polished it. I did notice that even though my firing pin moved it didn’t want to come out of the housing till I gave it a little tap. There must have been some carbon build up around the hole where the pin sticks out. The head of my firing pin seems to be bigger in diameter than the shaft so I would assume the tip was getting caught on carbon build up when I tried to remove it. I reassembled firing pin components with EWL synthetic lube. I figured I could rule out some of the variables by doing these things. I still felt the cast boolits being engraved by the lands was probably the culprit. I then remembered I bought a Hornady comparator gauge to measure heap spacing off the shoulders of my fired Cases last year.

Here are my measurements of the fired cases...



And here are some measurements of the the cases I had ready to load up that I full length sized in my RBBS Dies. I basically followed the RCBS directions and lowered my die To my shell holder when it was raised. Then I lowered my shell hold and turned my die down approx a 1/4 turn like I do with all my FL sizers to size my brass.



These cases are all Remington from the same lot I bough new. So it seems like my case knecks are not getting bumped back when I full length size with a quarter turn down. Some are even longer than my max chamber length so I’m guessing this is why I had some resistance when chambering?


I also had a few of my boolit’s lube groove get shaved from my aggressive crimping when firing so I got out the chore boy and scrubbed even though I didn’t see any lead with the naked eye in case I had a lead ring jammed up in my action causing the chambering issues.



I had zero leading and none came out so that was just another variable to rule out.

I also noticed my case necks like they have a little bulge in them. This was after firing and also after full length sizing. I would have though my sizer would have smoothed it out? Maybe it’s an issue or the resistance problem? Here’s a photo of what I’m referring to...




So my question is should I be bumping back my shoulders a little or just work my action a little harder to get it to close up tightly? I’ve bumped shoulders back in some 243 loads and my groups opened up so I don’t want to have to bump my shoulders if not needed. I was shooting at the range, off the bench, so I wasn’t power stoking my action when cycling in the next round. It looks like most fired shoulder measurements are around 1.563 or a hair less and my unfired, sized cases are all over the board. Most seemed to be around 1.562” and some are longer than the fired cases. I would assume that’s from some being ladder tested with lighter loads. I can see about a half a dozen that measure 1.563 or larger which I would assume is where I’m running into the residence feeling when closing my lever that last 1/4”.

Anyone feel free to chime in.

[Jedman]

I am wondering if your sizing die is somehow allowing that small bulge in the lower neck after FL sizing. I can see it in your photos and it should not look like that . It seems to me that if I can see it in a sized case once you load a cast boolit that’s a little larger than .358 it maybe causing that slight resistance when closing the lever the last little bit.
If so you may not be head spacing on the shoulder at all with your seating die set up as it is.
I would measure a loaded round before and after firing and see if it is slightly larger after firing and if the bulge is gone in a fired case ?
Otherwise I would take a sized and primed case that is not loaded and fire it in the gun and after extracting it if the primer is proud of the bottom of the case then you need to have your sizing die backed off some until a it comes out flush to know your shoulder is in the right place.

The slight bulge in a sized case is still not right as I have a 336 in 35 Rem. and my dies don’t leave a sized case that has a bulge.

Jedman

[357Mag]

Triple -

Howdy !

Shooting .35 Rem in my M-336 XLR......

I am a only using the rifle for target work, shooting ( thus far ) “ reduced “ loads.
Am not using any neck crimp, and bump case shoulders .001” after each firing.

IMHO - don’t fret about the expanded area seen on your case’ necks. I shot a bench rest grade
bolt rifle chambered in .357AutoMag, but w/ chambered and barrel set-up as .358” calibre ( for shooting rifle bullets including “J” words ). My fired cases nearly looked like they had 2 shoulders..... an artifact of J.D. Jones using a .357AutoMag pistol reamer he had, to cut my chamber. Accuracy was still superb, and my custom Hornady “.358 AutoMag “ shoulder bump/bushing NS die did not size down the similar notable neck widened area of my brass..... which resembles what you are seeing.

I am neck sizing my .35Rem brass using a LEE collet NS die, and it works great !
To me, the larger issue is whether one has to ( or wants to ) FL size ? I use Remington-brand .35Rem brass,
and don’t want to work harden any of them. With my reduced loads, just doing a shoulder bump and neck sizing suffices ( my loads... my gun ).

I have done the bump on .35 Rem shoulders using a .380ACP die.... the beveled entry hole interfacing w/ the
.35 Rem case’ shoulder, nicely. But then.... I religiously do an outside neck turn on all my cases, to make them more uniform. My case necks have .010” neck wall thickness, which again.....works just fine for me; as I do not use a crimp on my loads.

I DK if any of this helps ?


With regards,
357Mag

[Tripplebeards]

I believe you have to right that bulge is caused from being expanded in my 336 chamber when firing. I looked at some of the pics of some of my loaded cases before firing. Here is also a pic of my micro groove marks when seeing if my dummy round would chamber.









So the bulge must be happening when the case expands in my chamber and is the way Marlin cut it. Either that or just can’t see the bulge in the above photos of my loaded ammo. I still would have thought when full length sizing it would smooth that bulge to even out with the rest of my case neck? No way to turn the cases after they are fired in my gun I guess.


Since I’m not really bumping the shoulders back when FL sizing my brass I’m wondering if I don’t have my sizer die screwed down far enough?

[Tripplebeards]

Later today I’ll smoke the neck area with a match and keep lowering my FL sizing die till I see I see it scraped off and a completely sized neck all the way to my case shoulder. I’ll measure head space to see if I bumped the shoulder as I go.

[Tripplebeards]

The case neck issue was caused by not lowering my FL size die down far enough. When I added up all my fired case measurements and averaged them I came up with 1562.25" using my Hornady case comparator. I adjusted the FL sizing die so my average head space measurement is now 1560.39". The necks are now smooth all the way to the shoulders as well.

[357Mag]

Tripple -

Cool beans. Press on.....


With regards,
357Mag

[Tripplebeards]

Hers a pic of the re sized cases and my hornady comparator measurements of some of them after I adjusted the die properly. They are on average .002” shorter than the fired cases.





I would assume these will chamber just fine now with zero lever spring back. I’ve just been reloading for mostly bolt actions over the years so if I get resistance my bolt still drives it home. Started loading ARs a few years ago. The first one I might have just got lucky as they chamber and feed fine. My AR10 in 243 I had to measure headspace to get them to cycle properly as well.

[Tripplebeards]

Tried the re sized brass yesterday and they all fed just fine.

[Neverhome]

Glad your issue is solved.
I wanted to comment on your lube ring picture. I get precisely the same lube ring in my 357 mag encore barrel. BUT only when firing at magnum velocity/pressures. If I fire the same bullet loaded and crimped identically but at 38 Special levels it doesn’t happen. I posted about it a couple years ago and I believe the consensus was it was lube filling the gap in the end of the chamber between the case mouth and leade. Not a problem apparently and was deemed a positive in the thread. That being said, it’s all just internet conjecture really.

I’m curious about where you landed with it.