Home Forums Lever Action Central Marlin 336 Lever Actions 140 gr monoflex for 30-30 problems

�140 gr monoflex for 30-30
Using Marlin 336c, handloading 150 gr Sierra FN, 30 gr of IMR3031, getting 2.5 inch groups at 100 yds.
Handloading 34.1 gr Leverevolution behind a 140 gr monoflex, getting 14" groups at 100 yds. Hard to keep them on the paper.
Using Lee Anniversay press with full length resize, and the factory crimp die.

Only thing I can see is that even with die and adjusting screw turned all the way in, it only seats the bullet to the bottom edge of the top cannelure, so when crimped, the case doesn't move into the cannelure. Checked when firing, and there was no bullet movement.
The other thing is the shape of the bullets. The 150 gr. has almost no taper, so when fired, it doesn't have far to go before engaging the lands. The tapered 140 gr. looks like it would have to travel much further, giving it a chance to wobble around a bit first.
Does the bullet need to be seated shallower to allow for that?
This one has me puzzled, and wondered if anyone has run into similar issues, or just has any ideas.

I have not loaded this bullet but have some thoughts. First thing I suspect is the rate of twist may be too slow to stabilize the bullet. Any of the monometal type bullets on the market are much longer for there weight than lead core bullets. Length not weight is what causes stabilizing problems. I would try shooting at a closer distance and see if the bullets are keyholing. If a bullet is not stabilized coming out of the barrel it can sometimes settle down enough in flight that at longer ranges accuracy will suck but the bullets will appear to hit the paper square. My 22-250 will not shoot the heavier barnes x bullet. At 50 yards I have obvious keyholing at a 100 the bullets are almost hitting the paper square.

The bullet might not be engaging the lands very well either. There is a smaller bearing surface to begin with and the monometal bullets don't expand to fill the bore like a lead core bullet will. When a cartridge is fired the bullet expands slightly and engages the rifling. A lead core bullet having the soft core expands slightly more engaging the rifling better. If this is the case even if the twist rate is ok the bullet still might not stabilize. You could check this by testing the bullet in ballistic gel to see what the rifling marks on the bullet look like.

Another really out there possibility is Hornady makes two versions of this bullet. One for the 30-30 one for the 308 marlin express. I am sure the box says for 30-30 but are the right bullets in the box? Might want to call Hornady and get the dimensions the bullets are supposed to be for the 30-30.

Nearly all bullets will shoot more accurately the shorter the jump to the lands is. I would try loaded them as long as you can. No need to worry about a cannelure with the Lee Factory Crimp die you can crimp anywhere on the bullet.

With all this said here is what I would do. First confrim the bullets are not keyholing and the correct bullet. Next try loading longer. Try different powder charges. I would also try different powders. If none of that solves the problems go back to the sierra.

Where are you getting the reloading Data for the 140 gr monoflex bullet? That seems like a stout load with the length of the bullet . I would look for different Data .. maybe email or call Hornady I used to use IMR 3031 for 30-30 and 45/70 but went to different powders..over the years...

Yep, you'll have to email Hornady, they don't have reload data for the monoflex posted yet. May also want to try the Hodgdon LVR powder.

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The flex tip bullets did not shoot well in some of my rifles so I went back to the proven loads. The perceived advantage of the flex tip is mostly advertising hype anyway. Compare the ballistics of a flex tip and a Speer at the same velocity and you will note that the point of impact at 300 yards is only about one inch difference. Most rifles are not accurate enough to show any real advantage.

The loading data came from Hornady in response to my request, and I am using Leverevolution powder.
Their data came from tests using Win Mod 94 with 20" barrel with 1 in 12 twist.
They tested 7 powders in addition to Leverevolution.
Their max load for LVR was 35.1 gr giving 2300 fps. I backed down one, to 34.1 gr giving 2250 fps.
I can post all the data if anyone is interested.

As per another suggestion, I checked bullets, and they are the correct ones for 30-30. Easy to tell as the ones for Marlin express has cannelures much farther back on the bullet.
I am a newbie at reloading, and have minimal equipment. I want to try seating the bullet higher, as I think the jump to the lands is too far, given the shape of the bullet. How do I determine how far it is from the lands? I know it shouldn't touch the lands because of case pressures. Would appreciate some tips on this one.

At 100 yds, there appears to be slight keyholing.

The easiest way is with one of these OAL GAUGE . It allows you to find the the length to the lands you can then reduce it by whatever distance you desire. The gauge can usually be found cheaper elsewhere just do some searching online. You also need the modified 30/30 case. All it is is a case that is threaded at the base to thread onto the gauge. Once on the gauge you place your bullet of choice in the case place the case/gauge into the chamber push the brass rod until you hit the lands. Tighten the set screw remove from chamber and measure.

The other way you can do it load several dummy cartridges of various lengths. Blacken the bullets with a sharpie and try them in the chamber. Eventually you will see marks from the rifling again measure the length and then reduce it by whatever distance you want to be off the lands.

Anything is worth trying but I don't know how much difference the length is going to make. If you see keyholing it is typically from a rate of twist being to slow for the bullet. Sometimes a increase in velocity can help. So the reduced jump to the lands might improve velocity slightly. Or you could try slightly increasing the powder charge.

Going back to my first post and my 22-250. Barnes was very helpful with my issues. They offered a lot of good info. They had tested the 53 grain bullet extensively. A 1in14 twist was too slow they found in the 22-250. But in the 220 swift at higher velocities the same bullet worked fine in a 1in 14 twist. I was also told that it was not the first time they found velocity increases were able to overcome twist rate problems. So maybe in your case it might be the same. Final thought on the twist rate have you checked the twist rate of your barrel?

Just did a quick check the marlin is supposed to have a 1in10 twist. So you should not have a problem. But stranger things have happened. You pretty much in uncharted territory. You are running this bullet differently than the factory test. The winchester has traditional rifling opposed to the microgroove rifling in the marlin. Microgroove rifling is very shallow. Again I am thinking you are not getting a good engagement with the rifling and not imparting enough spin on the bullet to stabilize the bullet. Just another possibility as the faster twist should definitely stabilize this bullet.

You could buy a box of factory shells and see if your rifle shoots them. That is what I did with the original LeveRevolution 30-30 ammo. My reloads equal the accuracy with the factory shells. I also use the Hodgedons LVR powder. My next step will be to chrono them.