key holed at fifty yards

[shotstring]

Misfire, at 1000 yards, 1,000 fps at bullet arrival on target seemed to be the necessary velocity to reliably prevent keyholing.

[35remington]

Shotstring, very, very few .45 caliber bullets will be making 1000 fps at that range. No blackpowder load will do it, and smokeless out of a .45-70 won't do it either.

Realistically, bullet velocities will be in the 750 to 900 fps range depending upon load, bullet shape and velocity. Closer to the lower figure.

[Misfire99]

Well first off I am keyholeing not tipping. It's so bad I could see it with my spotting scope. There is literally the outline of the side of the bullet, with flat base and rounded tip, in the target.

As for alloy. These are store bought Laser-Cast 500 grain FP. These are the hardest cast bullets I have ever seen. They are supposed to have silver in them. This tells me they come from a galena mine that, most likely, has to low a content of silver to make it profitable to extract the silver. When I setup the OAL for a round I drop a rod down the muzzle into an empty chamber and mark the rod with a file. I then drop the bullet I am going to use into the throat and hold it there with something. I then drop the rod on top of the bullet and mark the rod with a file right at the muzzle same as with no bullet. This gives me the OAL for that bullet engaged in the rifling. I used the same file I use on a steel rod to score one of these bullets. On the steel rod I get a very nice score that I have no problem finding with my finger nail. When I do this to one of the laser-cast bullet I can see the score line but can't feel it with my fingernail. These bullets are hard!!!

Soon I will pull the bullets and load them to 29 grains. This is the top end of the <28000 range. And also the top end of the pressure range for my Handi-Rifle. I probably won't get this done and tested until Monday or so.

[35remington]

As long as twist is in the region of 1-20, you should be okay for stability. Usually, I find severe keyholing a clue that your bullet is undersized.

My Microgroove Marlin .45-70 lever will throw .457-.458" bullets sideways through a target for the first several shots. Then, as the barrel leads and closes down a bit, accuracy becomes pretty decent, then goes to hell again as more shots are fired.

Which is why you see a lot of shooters here recommending .460-.461" if your chamber allows it. I haven't run into a .45 caliber rifle that won't chamber or shoot this diameter to date.

[mooman76]

Misfire 99

I don't know about the more modern 45-70's but my Trapdoor will keyhole with lead that isn't pretty soft. That could be the problem maybe but others that have your type gun could say better!

[ammohead]

Misfire,

How consistant are the bases of these boolits. Imperfections on the bases of bullets can cause all kinds of problems.

ammohead

[shotstring]

35Remington, I didn't even think about the black powder guys and the silhouette shooters shooting at 1000 yards. All the competitions around here are for a max of 600 yards in that arena. The 1000 yard competition I was referring to uses jacketed bullets out of 6mm and 30 cal guns. Just threw the figure out for a reference. I think it is interesting to see how the large cast bullets and jacketed bullets compare in terminal performance - what similarities and what differences.

I would be interested in when the ballistic coeffecient breaks down with large lead 45 cal slugs and when they become unstable and likely to keyhole. I haven't been able to do the testing I have wanted to do with 500 gr boolits out of my rifle as I have to drive a very long ways every time I wish to test a load. I thought this problem of low velocity short range keyholing an interesting problem and wonder what everyone's experience has been at super long range with similar caliber and boolit weight. With jacketed bullets at long range, as velocity decreases, eventually that bullet is going to destabilize and go sidways. I would think this would happen at some point with heavy cast boolits also, but I don't have enough experience shooting lead cast rifle boolits to know.

[Misfire99]

Well I'm all set to give it another test. I just loaded up twenty rounds. 10 of them are 500 grain laser-cast and ten are 500 grain solids. I got the solids from Midway in their blemished bullet sale. You never know when a herd of angry Cape Bufflao will charge down your street.

But where I live there have been a lot of Grizzle bear attacks. One guy got his face torn off by one swipe from a grizzlies paw. I live near Yellowstone and a lot of the food sources for the grizzlies are in short supply. Yellowstone is an active volcano and in some parts of the park the ground has gotten to hot that it killed the pine trees. Pine nuts are a big part of the bears diet. So now the bears are coming out of the park to eat the nuts that live around hear. We have wolves also. One of my neighbors bought a calf to fatten on his land. He hadn't fenced the land yet so he stacked the calf. He got up in the morning and the wolves had eaten his calf. Veal for breakfast sounds good to me. We have sort of a habit to look out side before opening the door. You never know what will be out there.

I took a couple of picture of the bullets and rounds they make up:
Here are the bullets.



And here are the rounds they make:


I will take my crono with me next time and see how fast these thing fly. Hopefully it will be tomorrow.

[Misfire99]

Well I just slugged the bore. Actually I cast it with cerrosafe. And I found that On the lands I have .449 and in the groves I have .4545. This is a microgroove barrel I believe. This does not make me a happy camper. I found a guy on line that might be able to deepen the grooves out to at lest .458 but right now I think I found out why it is keyholing. I will still try the test with the 29 grains of powder behind the solid and cast 500 grain bullet.

[joeb33050]

The Curse Of The Store-Bought Boolit is alive and well........just kidding.

If the powder substitution of Unique is the only variable changed--and the boolits behaved without getting poetic using the 5744........the Pedersoli shooter may be correct. The ROOT CAUSE as to WHY Unique prompts this anomaly--and the pursuit of same--would make me nuts in short order.

Of course, driving me nuts is more of a chip putt than a long drive.......but I digress. My response to such a course of conduct would be to relegate the Unique to the mid-range magnum revolver cartridges from whence it came--and get me hence to the gunshop for more 5744.

I have shot about 1.46 zillion 45/70 shots with 14/15 Unique, bullets from 457191 to 457125 and not a single keyhole that I can remember. Also, never saw leading like that, and I can lead a barrel! I hope he just runs out of the bullets.
joe b.

[Scrounger]

I would think the under-sized barrel would tend to drive up pressure, so maybe lowering the powder charge would be the way to go. Actually, the way to go is to send that puppy back to HandiRifle, along with your targets prominently displaying the keyhole bullet holes, and maybe the pellet you slugged the barrel with. I'd tell them to replace the barrel or give my money back.

[Misfire99]

Well I just got back from the range. The 500 grain solids shot a one inch group. The 500 grain cast had an eleven inch group with two of the three keyholed. I am not happy. I doubt that H&R will give me another barrel. It does shoot one inch groups with jacketed but nowhere in there literature does it say that they have a micro groove barrel. I don't know what I'm going to do just yet but I will keep all posted. And thanks for your help with this.

[9.3X62AL]

Based on your latest results--I would say that your lands at .449" aren't tall enough to fully engage a lead boolit given the .4545" groove depth. FWIW, the Ruger #1 is an eight-groove pattern with near-equal land and groove width, .449" x .459". You are talking a .00275" land height here, which isn't a whole lot of grab-ability. Note the highly sophisticated ballistic terminology there. It works with the solids, and will likely do so with conventional jacketed bullets--but things seem shallow for shooting lead, to me.

H&R/NEF is now part of the Marlin corporate umbrella, so you make indeed have a Micro-Groove barrel there. Most MG's require fatter boolits to shoot well, so why this tight barrel is acting this way is really strange to me.

+1 to contacting the maker--nothing to lose at this point, and maybe they will listen and act.

[leftiye]

Misfire, I cast my chamber on my handi riffle and mine has an oversized chamber neck, no freebore, no leade. Did yours have any freebore or ballseat, or leade? When the rifling JUST STARTS, there's a lot of pressure, and the rifling CUTS grooves instead of swaging them, lots of deformation.

Try searching here about micro groove barrels, a lot of guys who have them say they will shoot cast well. The hardness of the lead should be a plus, you could try sizing them to about .456 (good luck finding that size of sizer!- maybe a tight .457 Lyman, or just size .457 or lap out a .454 die).

H&R seems to be using a lot of Marlin barrels lately (funny thing- Marlin owns H&R)- rejects? I had to buy a .444 barrel (1 in 10 twist) instead of a .44 Mag. barrel, the .44 Mag had 1 in 38" twist (who'd do that to a buyer?) can't even imagine that working. If ya go with H&R's rebarrel offer, CHECK THE TWISTS!

[Misfire99]

What I am looking into is having the rifling cut deeper. There are a couple of guys that do reboring. I am hoping, note crossed fingers and toes, that they are good enough with their machines to just cut the rifling deeper. This would solve the problem. I have emailed them and am waiting replies. One of them is Quality Barrel Works.http://www.cutrifle.com/index.html

I have seen his description of what he does and I suspect that it might be possible. If you know the twist rate and can index off of one of the grooves then you should be able to do it. If he can I will post back to the group. I think it's something lots of guys shooting Marlin rifles would like to do.

I think I have to take a long hard look at buying the Marlin 1895 Cowboy lever action I have been drooling over. I have never shot a micro groove bore before. I think they leave much to be desired.

[35remington]

The Marlin Cowboy rifles have standard rifling.

Can't speak for your barrel, but Microgroove rifling is not a problem with lead bullets as long as it is dimensionally correct - and this can be said of standard rifling, too.

Look at dimensions, throating, and chambering as being the most suspect area before you get involved in the rifling type debate. It's too far down the list to fixate on as a cause of inaccuracy. See if they did everything else right first, including cutting the Microgroove rifling adequately.

[Scrounger]

I'm pretty sure they won't touch your rifling. Look at the price of your gun, man, does it make any sense at all to put another $100 in it for something that probably won't help anyway. Send it back to H&R. tell them the undersize bore is a safety problem, it drastically increases chamber pressure and could blow with factory rounds. They will be glad to put another $87 barrel on it rather than risk a lawsuit.

[chuebner]

Hey Pumpguy where do you get .460 bullets?

If you can still find one, Rapine made a .460-500gr. mold that is a copy of the old Springfield 500gr. arsenal bullet. My mold drops them at .4615 and I shoot as cast in the trapdoor and size to .459 for my rolling block. One of my friends has the H&R Buffalo Classic that slugged out at .459 and he was having fits getting store bought bullets to shoot. He now shoots my 500 grainers on top of 70gr. 2F GOEX and is very happy with the accuracy.

Charlie

[jack19512]

One of my friends has the H&R Buffalo Classic that slugged out at .459 and he was having fits getting store bought bullets to shoot.
Charlie

I must have really lucked out. I haven't slugged the barrel of my H&R Buffalo Classic 45/70 but I think I will now, just curious. But, mine shoots jacketed bullets really well and after experimenting with powders and loads my cast is starting to come around very well.


In all of my testing with cast I have never had a keyhole with this rifle yet. I tried shooting my cast bullets as cast but they do better when sized to .459. Also I don't use gas checks. I cast using straight wheel weights and with the 340 gn. cast bullet velocity is around 1500 fps. at this time with no leading.

[leftiye]

Those $89 dollar barrels actually cost a bit more than that. There's a $15 fee for fitting them, and shipping on top of that. Scrounger is right- whole new barrel for the cost of recutting one. He's also right about H&R should replace that one because of the non-standard groove diameter. Standard .45 cal. bore is .450 (surprise) with .458 grooves (or .460).