30-30 trouble

[XWrench3]

:killingpc first, i will warn you, this isnt going to be a quick read, but i will try to explain as much as i can. i have an old glenfeild (marlin) 30-30 with a micro-groove barrel. after initially leading the #$%& out of it, on my first cast boolit loads, i decided that i had better slug it to see just how big it was internally. well, i slugged it twice, and it measures a nice little 0.0308". so, i figured after reading several articles here, and on other boards that with the micro-grooves, you still need a larger bullet just to get it to bite well. so, i bought a new mold, and it cast bullets @ 0.312". great. well, at least i thought. i tried several of them, and they shoot fine, no barrel leading at all (they are lubed). but, i really have to squeeze the lever to get them all the way into the chamber. at first, i thought that maybe i had a few cases from when i first started reloading for this gun, where i did not have the die set right, and the cases did not get resized all the way. but that is not the case. so, tonight, i sized down some to 0.311. i installed 2 with, and 2 without gas checks. still have to pull hard on the lever. the o.a.l. is 2.550", and i did check, the boolits are not enguaging the rifling. i have another sizer, which sizes down to 0.310", so i tried that. but the same thing happens, only to a slightly lesser amount. if i use a hornady jacketed bullet, all is fine, so i am forced into believing that the problem is that the cast boolits are just to big. i really want to shoot cast boolits in this the majority of the time. but i still want to be able to shoot jacketed bullets for hunting. without sacrificing accuracy. the thought of having a gunsmith open up the chamber slightly has crossed my mind, but i do not want to sacrifice ANY ACCURACY with the jacketed (or factory) loads. i do not know if opening up the chamber 0.003" or so will hurt it or not. is there anything else i could do to aleiviate this problem? i thought about shaving a few thousandths off the outside of the case neck. but i forsee two issues there. 1) i am not so sure how much strength i would loose, 2) i dont have a way to do it, other than with a peice of emery cloth and a drill. which is not very precise. i think i would just end up messing things up worse than what they are now. anybody got any idea's??? thanx.

[geargnasher]

I have a similar gun, and shoot .310" boolits in it with most brass. You didn't mention what size the first boolits were that leaded the barrel, but there may be other issues as well. DO NOT enlarge the chamber neck if you want to shoot J-words also with any accuracy, as the boolit alignment in the chamber is critical to accuracy with either J or cast. You can raise chamber pressure considerably by having a binding loaded case neck, so be careful shooting those super-fat boolits.

Making a chamber slug or taking a cast will tell you your chamber neck and throat dimensions, that would be a good place to start.

I outside-turn my thicker case necks to clear, it's only a thousandth or two off of the total loaded diameter (half that off the neck wall) to get .001" clearance of the loaded round in the chamber neck. That's close to BR specs.

Gear

[Lead Fred]

Back your OAL off .005 and try again.

Those fatties might be bigger than a stock round.

[Echo]

Turning the case necks down .001 on a side will reduce the OD by .002 and might be enough for you to be able to easily chamber your rounds, and yet have a lead-free barrel.

[glenliz87]

I shoot cast in my Marlin 30-30 as well. I size mine to .310 but I found that my OAL has to be 2.525 and this works good for me. I cannot close the lever if I make them any longer than this. At an OAL of 2.525, the boolit is touching the rifling. The lever sometimes closes with a little more effort but at least it shoots accurate with no leading.

[Lead Fred]

You might use a OAL gauge with the cast boolit

[lwknight]

You might do OK with .309 sized boolits. Are you using a hard alloy? I would think that a 15 bmh would grab the riflings without skidding. I'm just throwing out some thoughts here.
All you really have to do is seal the barrel and 30-30 has enough pressure to make the boolit obturate the barrel anyway , I would think that only 1/1000 over size would get the job done.

[btroj]

I have a 70's vintage Mariln that had a similar problem. I found it was NOT bullet or neck diameter. My new RCBS sizer did not size down the body enough right below the shoulder. This was with the shell holder hard against the bottom of the die. I borrowed an old herters die form the FIL and it work great now.

I could not get cases that had been fired a few times to chamber easily even after sizing- and this was an empty case!

I was turning necks to no avail. Keep looking to see what is really going on with your rifle and good luck. Mine was the most frustrating situation I've had in reloading.

Brad

[XWrench3]

2.472"! o.a.l. Is where i ended up with these. That clears up the issue. Thanks guys! I am not really sure why i couldnt see rifling marks in the nose of the boolits @ 2.550. Maybe they are just to hard (50/50 ww/pb), or maybe the leade is long on this gun. I dont know. Anyway, that length is where the next crimp groove is at, so that works. These are very low psi loads, (4.2g of hp38) so i am not to worried about over pressure, but i will keep an eye on them. I do not have much worked up for fast loads with these yet, so i am pretty much starting from scratch anyways. Now, all i have to do is get a set of dies that do not want to pull the boolit out every time i try to seat it (the hole in the die is to small for the boolit nose).

[Jon K]

Modify or change the seater plug to fit the boolit, that will solve the seating problem.

Jon

[largom]

When you have a chambering problem like this, one way to check where the case/boolit is binding is to paint the whole cartridge with a magic marker. The binding points will rub the marker off or show up on the boolit nose if touching bore.

Larry

[runfiverun]

good advice above.
everybody gets so wrapped up in bore,bore,bore.
that they forget there are other dimensions to consider.
like groove and throat angle,and neck length to consider.
sometimes something as simple as neck length hitting the end of the chamber or being to short and letting the boolits base scrape there can ruin accuracy.
or the nose hitting the 300 lands as they taper down can cause problems.

[Doc Highwall]

Another thing that was not mentioned was the crimp. The reason I mention it is because in my 1885 Win in 38-55 if I don't keep the case mouth belling to a minimum it makes it hard to push in by thumb pressure. Too much of a crimp can cause the same problem.

[atr]

my first thought was that the ogive was engaging the lands,,,, and/or the crimp was bulging the case

here is what I would do.....
take a sized case, trimmed to the proper length and chamber it without any boolit,,,if the lever closes easily then you can safely eliminate that as the source of your problem.
next....take the sized case and drill out the back at the primer hole,,,,make a overall length gauge from a piece of coat hanger......(I will post pictures later).....
expand the case as you would for your boolit (or slightly larger)....now your boolit shold slide into the case mouth easily......
insert the drilled out case with the boolit and gently push the boolit out until you feel it touching the lands....set your home made gauge at that position....remove all and load a test round with the boolit seated just under what our test gauge was showing....try chambering that to see if your problem still exists......
DO NOT Crimp this test round.
if this test round chambers easily THEN,,,set your crimp
and test again
like I said the test gauge is easy to make,,,,and I will post a picture later today
atr