!st cast boolits through a micro groove

[FallRun]

Sent my 1st cast boolit down range yesterday through my Marlin 30/30 with a micro groove barrel. It was a 170 gr Laser Cast over 7.0 gr Unique. No gas check.
After the first shot I sent a dry patch on a jag down the bore and got very small shavings of lead on the patch. Don't know why but I shot a few more and also found out I was shooting way low and right. I was drivin tacks at 100 yards a week ago with jacketed stuff. I slugged the bore and it was 308 so I ordered the boolits at 310 but again guys I didn't use gas checks. could the gas checks be my problem? any help or suggestions ? thanx, Glenn

[35remington]

If the Laser Cast doesn't come with a gas check already you can't put one on it, as it would be a plainbase. A gascheck bullet has a step at the base of the bullet for the gas check to fit. I don't know of any major lead bullet supplier that sells gascheck bullets without the gas check in place.

How does the load shoot? You didn't mention. Striking low is typical for cast bullet loads that are much slower than standard factory loads, as yours are.

I presume you prepped the case properly for the lead bullet, and didn't just seat it using the seating die without flaring the case mouth first? Two die sets for bottleneck cases mangle cast bullets when they are seated. M die or flaring die is needed.

I'm also assuming you removed all jacketed deposits before shooting?

Excessive leading, if that's what you have, can be caused by a number of things. We need a little more information. Leading should not be a problem with your load and a properly prepared bullet.

[FallRun]

These bullets are made to except a gas check. There is a step at the bottom.
Also I did flare the case using the Lee universal expander die. As for shooting low, I was trying to hit a 5" steel plate at 100 yards with a scope and was about 6" low and 6" to the right. It seemed each shot got worse as I couldn't even compensate so after 7 shots I just went home.

[26Charlie]

Fallrun, A 5-shot group from the bench on paper or a big piece of cardboard will tell you alot about the problem.
The load you mention is rather light for .30-30, about a 50-75 yard load for varmints & small game, due to the low velocity - I would estimate 1150 fps. Not that it wouldn't kill at 100 yards or more, but the trajectory is arched, like a .22 bullet. It shouldn't require a gas check, but the microgroove rifling grips a bullet with a gas check better.

[woody1]

If the Laser Cast doesn't come with a gas check already you can't put one on it, as it would be a plainbase. A gascheck bullet has a step at the base of the bullet for the gas check to fit. I don't know of any major lead bullet supplier that sells gascheck bullets without the gas check in place.


YUP. LaserCast sells, or at least used to, a 311041 or similar with no gas check. I tried 'em once and couldn't get any gas check to fit. The base too large for any gas checks I had. They're harder'n the hubs of He!! and the lube is lousy. Now, Woody tell us what you really think! Some folks like 'em. My opinion is that if you don't have a perfect fit in the throat, you're going to have trouble with 'em. My take on LaserCast 30-30 boolits.


FallRun, have you slugged your bore? Do you know how large a boolit will chamber. I assume the .310's did. After you shoot a cartridge with a reasonably high pressure load is there quite a bit of slop if you stick one of those .310's in the unsized case? If so, you can surely go with a larger boolit. If you like you can PM me and I'll send you some of the group buy 314x120's in various sizes to try. I shoot 'em by the hundreds out of microgroove and non-microgroove 30-30's with loads similar to what you're using for short range plinking. Regards, WOody

[pumpguy]

FallRun- I have shot thousands of rounds in my microgroove 30-30. My load is 18 grains of 2400 behind a 170 grain 311041. The boolit is sized at .311 gas checked, and tumble lubed with Lee liquid Alox. I have also shot this same boolit with 32 grains of WW 748. Both loads are in the 1800-2000 fps range and are very accurate. They are good for about 1.5" groups at 100 yards with open sights. I really think the fatter boolit is the key in a microgroove barrel. FWIW, I shot about 250 rounds in this gun before I ever cleaned it. I have no idea how many condom bullets went in it before I got it or how many I put through it before I started casting my own and keeping track.

[uscra112]

I've lofted a ton of lead thru my .35 Rem 336 with a microgroove barrel. I also saw those shavings when shooting light loads with hard boolits. I think if you up your load they will disappear. I have the idea that Lasercast boolits are fairly hard. If so, you need a load using a fairly fast powder that generates maybe 1800 fps, or they won't obturate into the grooves properly. I never tried to determine whether the loose lead was blown off the boolit by gas blowby, or was shavings from poor seating practice, so I'm not 100% sure of that, but I DO know that accuracy with hard boolits won't appear until 1600 fps or so.

BTW XMP-5744 is my favorite propellant for everything up to 1800 fps with hard commercial pistol boolits.

You must use a boolit .001" bigger than groove diameter in microgroove barrels. No more, no less, in my experience. The microgroove displaces less lead as it engraves, so there's less chance that displaced lead will fill the grooves.

For my subsonic loads, I'm using 20:1 or softer.

Boolits with long bore-diameter noses don't work in microgroove barrels. The actual bore of a microgroove barrel is bigger than the nominal value. Boolits should be full groove diameter plus .001" for at least 2/3 of their length. Loverin styles work good. But boolits that are great in the .30-06 or the Krag aren't accurate in microgrooves.

The SAAMI .30-30 chamber drawing shows a VERY short leed, and it may be the source of those flakes all by itself. The leed may be cutting the boolit instead of pressing the rifling into it like it should, and the low temperature and pressure of that light load doesn't even blow them out of the barrel. (I only just now thought of this - it may seem crazy in the morning!)

I have (somewhere) an old Am Rifleman article that was written specifically to disprove the legend that microgroove barrels wouldn't shoot plain lead, and one of the things that gunsmith did to make the .30-30 a tackdriver with lead boolits was to re-throat it. Everything I've stated here I learned reading from that article, and it's all proved out for me.

[Glen]

Were you flaring your cases before seating your bullets, or were you just seating them like you would a jacketed bullet?

[Four Fingers of Death]

That boolit going fast enough?

[35remington]

The gascheckless gas check bullet is a new one on me. Haven't seen that before, but I shoot a lot more of my own cast bullets than I see others shooting commercial.

The shaving of the bullet could be related to bore misalignment, but most likely is due to the fact that you're shooting a hard unobturating bullet with a light powder charge that erodes the hell out of it. Regular ole leading looks like flakes too. You'll most likely have poor luck shooting it at any higher velocity sans the gas check.

How old is your rifle? This might have a bearing on what to do. Can you make a chamber cast?

It is possible to shoot hard bullets at low velocities accurately in a Microgroove. If they fit. And if you're willing to try a few things. And if you get a proper bullet.

Shooting a checkless bullet at low velocity in a Microgroove is really climbing uphill. Almost anything you try from here on out will be an improvement. A good first step would be checking the bullet or finding a proper plainbase one.

[qajaq59]

These bullets are made to except a gas check. There is a step at the bottom. You can get Laser Cast bullets that don't need the gas check, which is what I use. But if you bought the ones that will accept them, maybe you should put them on. And 7 grains is the starter load for that bullet with Unique so they're likely to have the trajectory of a slingshot. I use 10 grains and they go thru the chono at 1500 fps.