30-30 bullets keyholing

R

RockyMtnDan

New member
I'm having trouble with 110 Gr. bullets in a Marlin 336 30-30. at 100 yards The bullets are tumbling and going through the target sideways. The rifle was built in the 70s and has a micro-groved barrel.

The load is at the top end of the load table with an estimated bullet velocity of 2600 fps.

The bore and rifling appear to be in good condition.

I would appreciate any insight in to possible causes and solutions.

Dan
 

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The 110gr bullets have a very short bearing surface. It could be the combination of a short bearing surface, micro groove rifling and the velocity are simply "stripping" through the jacket, and not imparting the correct spin.

The simplest thing to try first is just back off the speed and see if the bullets stabilize. If they do, then the problem is solved. Some combinations just will not work, and those bullets, at that speed, in your rifle could just be one of those.

does your rifle shoot properly with the regular 150gr bullets? If so, its not your bore that is the problem, its the combination of factors.
 
It's 'keyholing ' . is the bullet jacketed ? The microgroove grooves are only half the depth of a standard rifling. Therefore the accuracy is dependent on the hardness of the lead and the diameter and match that to velocity.
If using a jacketed bullet also make sure there is no leading in the barrel.
Other than that measure the bore and bullet to see if there's a proper match.
 
Keyholes seem long and skinny for a short stubby 110gr bullet. Possible that jacket separation is happening after the bullet leaves the barrel?
 
Thanks for the ideas

Thanks for the inputs. I will both slow down the 110 Gr. load and try some 150 Gr. bullets. It will probably take a couple of weeks but I'll post the results. Dan
 
Interesting! I have loaded the same 110's in 30-30. Now I'm really wanting to see what they do.
If I may ask...
Why Micro-Groove? What is the purpose?
 
Easier to make and doesn't require the bllet to be distorted as much therefore better accuracy. Read my post above about lead bullet accuracy in microgroove.
 
Micro Groove may not be the issue, but maybe Marlin's faster 10" twist(vs Win's 12" twist). Usually folks shooting photon topedo loads out of fast twist 223's have these discussions, but I know Speer's 110 varminters are looking for an excuse to come apart at hot 30-30 levels. What 110 was the OP using???
 
Try a longer bullet such as the 125 grain Sierra.

Jack

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next we'll be having discussions about pointy bullets in tube magazines... ^^^ ;)

Out of curiosity, have you ever slugged your bore? It's usually an issue with lead bullets (flinging them sideways) if they're undersized for the bore. But jacketed with a small bearing surface to begin with are going to have the same issue if they're a tad small, especially when they're driven that hard. If they're already wobbling before they hit the muzzle, there's no way they're going to be stable on the way to the target.
 
Yes pointy bullets in a tube magazine can be a bad thing, doesn't mean you can't shoot pointy bullets in a traditional lever action. I tried the 125 grain Nosler ballistic tips in my M94 and I'd only load two cartridges at a time. My rifle didn't like them very much, about a 2" group at 50 yards was the best I could average. I just hope Hornady starts expanding their flex tip bullets as I'd like to play with some lighter 125-135 grain mono metal bullets in my Winchester.

Besides not all .30-30 rifles are created equal there are several out there that can run spitzer type bullets. In a lever action you can find a Savage 99 and it alows the use of spitzers. In bolt action rifles there is the Winchester models 54 and 70, Savage/Stevens/Springfield had the 325 and 340 rifles, Remington had the 788. Then you have the H&R Handi Rifles and Toppers, as well as the T/C Contenders and Encores in .30-30 as well. Plus there were several over/under .30-30/shotgun combos out there as well.

I have the M788 and with about any factory ammunition it will shoot sub 1" groups at 100 all day long. With Hornady's 165 grain Leverevolution it shoots sub .5" groups on a regular basis. I haven't really tried much else in it but I did try some 124 Sierra's and 135 Hornady bullets but so far I haven't found the right load.

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Should I have added "Dripping with sarcasm" to the earlier post? I would have figured it was pretty obvious. But thanks for covering it anyway--now maybe it won't stray off track for two pages worth of argument on the matter while forgetting the purpose of the original topic.
 
I belong to a group locally where 12 of us shoot the Marlin 336 in 30-30. Some of these rifles have a low shooting count and some are very old and worn. The group has slugged all the barrels and we end up shooting rounds between .308-.311 for accuracy. You may want to slug your barrel and see where it ends up on the scale for better performance.
 
Before even reading your post I knew it had to be a Marlin.
My one, and only, Marlin could not find paper at 25 yards and the rare times it did the bullets keyholed.
New ownership now, maybe they have changed but I don't plan to risk it.
 
Gentlemen, Thanks for all the info and ideas. I won't make it to the range until next weekend but I did drop to the the bottom of the load table to get a round that shoud be moving at 2250 fps. I will also pick up a box of 150 Gr. on the way so we will see if those work.

Mete: The bullets are jacketed Speer's and the bore should be clean. I've scrubbed with with a brush and Hoppes until the patches come thorugh clean. As far as I know that's all it takes to clear up lead fouling but if someone has another recommendation I'll give it a try.

BerdanSS: Based on the serial number this Marlin was manufactured in 1962. The bore looks to be in good shape and I know that since the 70s it has only had a few 100 rounds though it.

The load is to be something light and easy for my daughter to shoot and at the same time reach out a bit (200 yrds) for coyotes.

Tom M: The holes in the paper do look longer than the bullets but it is an illusion. I pushed one of the unloaded bullets through and they fit exactly. the bullets are Speer but they don't appear to be separating.

Rangefinder: I have never slugged a bore but I suppose there is post elsewhere in this forum that will provide directions. I did fit one of these unloaded bullets into the front of the bore and there is enough friction that I can't push it in by hand.

Buzzard Bait: I was supprised as well. The main cluster of shots is acutally from 2 different hold points. The top 5 held on the bullseye and the bottom 4 at the lower point of the diamond. That 4 shot group is just over 2"!! I expected performance from tumbling bullets to be much worse.

Rifleman1776: If I had purchased this it would be on the way out the door already but It came to me through by father and I've got to get this figured out so I can pass it to my grandkids one day.
 
I tried 30 carbine 110gr bullets in my marlin 30-30 and didn't push them as hard as you are. They never did shoot very well. I have owned 5 marlin 336s and a glenfield model 30 with a half magazine and everyone gave good groups with 150 and 170 gr bullets. I really like 30-30s and could do all my deer hunting with one and never need more gun. Its a great handloader cartridge.

If you want to shoot coyotes at 200 yards you might want to get your daughter a 223-243 type of rifle. Since you handload a 243 with 80gr loads reduced to 2700-2800fps should be a light kicking round and be fast enough for 200 yard shooting. Plus 100gr bullets could be her deer rifle. Maybe a light rifle like a savage youth or a ruger american rifle.

I haven't handled the savage but did get to look at the ruger. It seemed like a fine rifle for the low asking price. Too bad they don't offer it in 223 or 22-250.
 
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