Couple of questions re Marlin 336A

[robroy]

I just had my new to me 336 A in 30-30 out for the first time. Using Ranchdog TL165 sized @ .311 on top of 2.2 cc IMR 3031 the first five shots were in a 2" group at 50 yards. The next 20 stayed inside 6". I don't see any leading. This is a pre-microgroove (Ballard) barrel. I plan to give it a good cleaning and try again.

Another thing happened: The lever didn't close completely on a couple of shots. On these few the friing pin didn't strike the primer hard enough to ignite the round. when the lever was squeezed up tight to the tang after cocking the hammer, the rounds fired. The detent and the rest of the parts that keep the lever closed all work with no round chambered and also with most of the 25 rounds I fired. I wonder if the rear of the fireing pin was misaligned enough to rub or catch on the inside of the bolt and not deliver all of it's energy to the primer.

Could the cases have been just a bit too long and caused the action to not go completely into battery? These were full length sized but maybe I need the die just a bit closer ro the shell holder.

[Gtek]

Open the lever and you will see a little piece sticking out of frame behind trigger. That is part of the safety link built/designed into function. Being an "A" that girl has some age and miles on her. Might be a good time for COMPLETE tear down and clean, bolt, action guts. Might want to try a little KROIL on that button and work in, see if that wakes it up. 50 or so years of God knows what sprayed, spilled, or drug through. Gtek

[geargnasher]

Could be insufficiently sized brass, could be bad leading accumulating in the throat/leade area (which would also explain your loss of accuracy), could be lots of things. Check for throat leading through the ejection port with a light shining in the muzzle, if it's there you'll see the shadows of the crusties in the first inch or so of the rifling.

Headspace is dicey in my experience with the 336, you really ought to invest in a headspace guage for your caliber and see what's going on. Adjust your seating die to just bump the neck back a couple of thousandths from where the gun puts it when the case is fired.

Gear

[kelbro]

I had the same problem with that bullet in my Marlin and Win94. No issues with other bullets. Had to trim the brass back to get it to work properly.

[robroy]

Gtek: I found the name of that part in the distructions. It's the trigger safety block. After I removed the bolt to look at the barrel I agree, this one needs a complete strip and cleaning.

geargnasher: As part of a good cleaning I'll look for lead as you suggested. When you speak of a headspace gage do you mean the gunsmith's tool used to set a barrel when chambering or a special reloading tool? I've chambered a couple of rifles and used the first sort. For rimmed cartriges it only gages the space between the bolt face and the cut in the barrel face. I''m guessing you mean something more precise than a go nogo at the rim such as a good measurement from bolt face to shoulder plus or minus .0005". I'm checking catalogs for such a thing. Point me in the right direction if you will.

kelbro: I had'nt checked case length beyond setting my caliper to 2.039 and using it as a go nogo. None was too long.

[rhouser]

If you were using someone elses brass, you may have to push the shoulders back with a full length die or a bump die to get your brass back to headspacing on the rim. you could have a legal overall length and still have the shoulder prevent the case from chambering. Try cycling all your brass empty. You should find any "pushed up" shoulders by doing this.

Ranch Dogs bullets work in my Marlin 30-30's because they are FAT. If you have a tight chamber, then, you might have to shorten your brass a touch if needed. Because you said it was only a couple for rounds that wouldn't seat, I would check your brass first by chambering every piece.

One last thought is watch your crimp. I have put a small overcrimp on a few rounds that basically Bulged the Neck of the cartridge and these rounds would not chamber.

Just my 2 cents... rc

[geargnasher]

I was speaking of the run-of-the-mill Clymer no-go rim gauges. There's no telling how deep the chamber was bored or where the barrel is set. You can simply oil the base of the barrel and use a speck of modeling clay on the front of the case rim and chamber it to see how much room you have. If you select a boolit that will cycle and yet push firmly against the throat when chambered it will keep the case head against the bolt face and any descrepency in chamber length will be made up for when the case shoulder blows forward. If you neck size at that point the shoulder will do the headspacing after that. Obviously you want to be careful of too much unsupported brass hanging out past the chamber.

Gear

[mainiac]

I have a old 336a in thutty-thutty as well.I shoot the noe copy of the same boolit your shooting.It shoots very well,crimped in the groove,the boolit just hits the rifling when chambered.Only issue i have with my rifle,is i have to run turned necks,cause i want to run a .311 boolit,and with standard cases,its like your saying,lever closes hard,because theres no clearence.

My rifle has a .332 neck diameter,dont know why a factory rifle was made with a tight neck like this,exspecially a levergun.......

This may be something to look at,with your gun.O-ya, my bore is like slightly over .310,,so thats why i cant shoot .308 sized boolits.

[Old-Win]

I recently started shooting a Marlin 36 D prefix. Is it typical for these Marlins to have a .310" bore? Sounds like most of you are shooting .311" bullets in them. Thanks

[Zim]

I tore apart an old Winnie & found the firing pin gummed up with oil & dirt. Make sue the firing pin is free floating.