Keyholing ---2 questions

[Southern Shooter]

Are these signs of keyholing? What causes keyholing?
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42808

42810



Thanks

[geargnasher]

Yup, that's the beginning of it, another 100 yards they might hit sideways. Boolit too small for the barrel usually causes it, or gross instability problems, unsquare boolit bases, damaged muzzle crown, really bad nose slump, etc.

Give us some details of the gun and load.

Gear

[303Guy]

If you could just capture one of those boolits ... Another possible cause - gas cutting? I don't know since I've never captured a keyholing boolit with gas cutting.

I wonder what would happen if you were to up the powder charge? Would it obturate the boolit and improve things or slump the nose more completely and evenly?

The undersize boolit is the most obvious and simplest thing to check, right alongside the crown.

You could be sizing the boolit base down on seating in the case neck. Just possibilities.

[303Guy]

Had a closer look at your pictures. Funny how they're all leaning sort of to the same side! Undersize boolit starts to look unlikely as does off-square bases and nose slump. Was the target square to the boolit path? Just checking. Ok, so I'd look closly at that muzzle crown.

The same side key-hole effect would be due to the boolit yawing in sinc with the spin indicating something happening at the muzzle. The early 375 H&H bullets did that making them poor close range performers until the makers increased the bullet weight and/or design perhaps? This did not effect long range accuracy which is what the gun was designed for but it caused penetration problems on big game at close range.

[Dave C.]

They look like 38 Special,HBWC. Am I right?

Dave C.

[Crusty Deary Ol'Coot]

Or possibly a rate of twist, bullet wt./length or velocity.

I recall back quite aways having long heavy "J" bullets out of a .30 Harrett, key hole even close up.

Wasn't trying to hunt with them, so it was really not a problem, except that bullet just did not stablize in that gun.

Keep em coming!

Crusty Deary Ol'Coot

[Tatume]

Perfect 38 Special wadcutters will keyhole at ranges greater than 50 yards.

[runfiverun]

they look like they are clocked within a quarter turn of each other.
and the further clocked [to the right] they are the further to the right they are on target.
they are unbalanced.
either under or over.
if your load don't look right change it.

[geargnasher]

Here's a nose-heavy boolit design that's notoriously difficult to stablilize, even at 195K rpm.

http://castboolits.gunloads.com/imagehosting/thum_89094e0a71a1d983d.jpg (http://castboolits.gunloads.com/vbimghost.php?do=displayimg&imgid=1314)

Gear

[John Boy]

Or possibly a rate of twist, bullet wt./length or velocity.
The stability of the bullet could be caused also by bullet weight and length and velocity and add diameter for a given bore twist

But the holes in the paper are round with no signs of a normal key holing bullet! So, have to side with 303Guy. I've had the same kind of POI's with the target mounted on cardboard with the cardboard bending when the bullet hits

[Southern Shooter]

Hello, Folks. This is the bullet that I have written a about in a number of threads. I love it. It is being fired from my Ruger SRH Alaskan .454 Casull.

It does NOT show any of the keyholing signs until I load it up with 23.5 grains of W296. From 21.0 - 23.3 grains the bullets make very nice, clean, round holes.

Also, if this is something to consider, the targets are about 1.5 feet above what would be a straight-on aim. So, it is NOT a case where the "target square to the boolit path"

What say you?
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[geargnasher]

I say it's a WFN which is famous for trying to swap ends past a certain yardage. 44Man will be along shortly to tell me I'm full-o'-bull, I'm sure, but I've had both good and terrible luck past 50 yards with hot .44s and WFN boolits. If the nose had less mass or was hollow-pointed (not good for a hunting boolit) it will fly straighter faster and further.

Gear

[runfiverun]

it's not the whole boolit wobbling.
most likely just the base.
notice it didn't do it till you bumped up the speed?

[303Guy]

But why would the wobble not be random? So, something is destabilizing the boolit and it only shows up at a certain powder charge range. Curious.

I'm wondering if the destabilisation is due to muzzle lift. That's about the only thing that would be consistent and would become significant enough to have an effect on that boolit. Small variations in powder charge or boolit weight could account for the less than perfect wobble sinc.

By the way, I didn't seriously think the target squareness was responsible although it has done it to me. The symptoms are quite different with the edge of the paper being swung away to one side. In this case and with Gear's the boolit has a base wobble.

[geargnasher]

303, a boolit is a gyroscope. It tips as it spins, but it doesn't just flail about like spinning a bent straw (unless of course it IS bent). It can trace the line of departure, but actually be pointed at an angle way off from the line it travels. Of course this introduces some aerodynamic drift as the nose planes into the air, I think that was what was happening in the target I posted above. Note how the 1,2,and 3 holes were all off the same way, and the holes were more round as the load worked it's way toward the center (POA). The boolit was angled to the left as it flew to the target, probably 20 feet or more to the left from muzzle perspective and target distance judging by how elongated the holes are.

Gear

[runfiverun]

the target loose/backer thing usually shows long radial tears.
look at gears pic. his is clocking over to the right also.
guess which way the rifling faces.
the puzzling thing is the way they walk the holes to the right and the tabs do too like they are taking that much more of a turn to get to the target and are that much more further away from the aiming point when they get there.
the weight forward is causing the issue.

[303Guy]

After zooming in I can see holes 4 & 5 are much rounder with 4 being almost perfect.

If a boolit were travelling in a spiral path the spiral rate would slower than the spin rate but the boolit can have a yaw rate slower than the spin rate too. If the yaw has the same rate as the spin then it's a wobble. That might explain the consistent lay of the key-hole but not 4 & 5, well maybe if we consider that there is more than one force at play here. (I can't describe it but I do understand the mechanics and dynamics of bullet flight path).

I see no sign of spiral flight path or 'yaw' if one differentiates between 'yaw' and 'wobble' which is really the same thing but different.

So, the offset kick that the boolit gets as it leaves a recoiling barrel would induce a wobble which would result in a consistent 'lay' of the key-hole. Unless my whole theory is BS which it could be.:???: But you guys have good heads on ya so your pondering would help to confirm or dispel the idea - which is all it is.

[GabbyM]

Looks obvious to me.

You’ve a plain based boolit shooting well then after upping a charge of WW296 they wobble.
Conclusion in my small mind is you’ve reached the point to where that bullet design needs a gas check to stand the pressure. 454 Casull will make far more pressure than a plain based bullet can stand up to. I make the Lyman bullet with gas check for the 454 Cassull.
No limit with that one.

You need to think of that round as you would a rifle round. It can over pressure a plain based bullet. I’d not sweat it to much. Just find a load it likes and run it. I’m sure it will thump plenty hard on both ends .

For those of you not familiar with the 454 Casull. My Lyman book has loads up to 53,800 C.U.P.

Running a bullet heavy for caliber as a 360 grain is in the 454 Casull. You’ve set yourself on a thin edge. Deleting a gas check just double downs on the whole issue. No mystery involved here. I’m no fan of heavy for caliber boolits. However you can with this 360 grain bullet achieve good performance at lower pressures. Just don’t think you can exceed the performance of a standard gas checked 325 grain bullet. Simply because you have more lead involved. Plain based bullet simply will not stand up to the rifle level pressures of a 454 Casull. But there is no law written saying you must shoot every round at max power.

[303Guy]

Ok, that makes sense. It doesn't tell us why the wobble is so consistent. Deformed base yes, but how does that make the boolit wobble or do they always wobble a little then dampen down as long as the base is undamaged? Or is it to do with cylinder alignment producing a consistent base damage? I've had yaw or wobble with a pistol (auto) boolit and it was random.

[GabbyM]

Ok, that makes sense. It doesn't tell us why the wobble is so consistent. Deformed base yes, but how does that make the boolit wobble or do they always wobble a little then dampen down as long as the base is undamaged? Or is it to do with cylinder alignment producing a consistent base damage? I've had yaw or wobble with a pistol (auto) boolit and it was random.

All true but when I overdrive a cast rifle bullet the groups can go from one hole to three inch with a half grain of powder. That can be with plain based or gas checked.

What I was inferring with my first post was the 454 Casull at full power is to much pressure for a plain based bullet so a reduced pressure is more than likely to be the load of choice.

[303Guy]

This makes me wonder whether a smooth side can handle a bit more pressure than a grooved boolit. For equal length a smooth side should be more stable but there is more metal to support the front bit. Just wondering. I haven't done anything like near enough testing and besides, I don't have a Casull. It would be interesting to see how an identical basic shape boolit without the grooves would perform with the same powder charge. A possible test would be with a harder alloy.

[Mal Paso]

It would be very cool to capture one of these boolits. Stuffing Box?

[Echo]

They look like 38 Special,HBWC. Am I right?

Dave C.

+1 - typical for those @ 50 yds. Danged accurate up to 50 yds - can't keep them on the paper @ 100.

And I just read the rest of the posts, so Never Mind comments on 38 HBWC

And ditto Dave C.'s signature, plus NT Team Match medalist...

[303Guy]

Well that's interesting, it being the boolit design. That's something to bear in mind when making my own boolits and having poor results - not that a long rifle boolit should have such issues but still.

[geargnasher]

A boolit needs to be lighter on the front end or it will be unstable at longer ranges most of the time. This is why WFN and full-wadcutter designs aren't the best for long range. Hollow-pointing helps immensely. Imagine a boolit as a smooth cylinder, balanced in the middle. Now, subtract the volume of lead missing from the lube grooves. Then subtract the amount for the nose profile. If the amount from the grooves is greater than the volume subtracted for the nose profile, the boolit becomes nose-heavy and would shoot better loaded backwards.

Gear

[afish4570]

Had keyholing visible at 10 yds. after barrel was becoming leaded to point rifling must not have been gripping bullet properly (cast bullets). I clean barrel with patch and piece of copper Chore Girl to remove leading and continue......afish4570

[44man]

Strange things happen so I can't say much.
The strangest bullets were 240 gr from S&W 29's. Watching the spiral flight around the bullet path was always fun but they always hit nose on at even 200 meters and would shoot 1/2" groups at 50. Going to a 250 gr made the bullet stop the spiral. Rugers did not spiral with 240 gr so it was just the twist rate difference. If anything the S&W was more accurate. I had to conclude that a slight over spin did not hurt anything.
Yes I do shoot WFN boolits to as far as 500 meters and watching through a spotting scope shows good flight and holes in paper are round. Yet I can't dispute what others find because I have no answer.
There was the 30-30 boolit from the TC Tender that would shoot pennies at 100 as long as I put the check on. Without the check they would be full sideways at 50????
Then the test 405 gr, .44 boolits sent us that made oblong holes at 50 because they could not be spun up. Then the silly 700 gr for the .500 S&W, a pure waste of lead. Same when trying to shoot very heavy boolits too slow and trying to get groups.
Then we get to the PB! They are all I make my molds for now and have gone to 1800 fps in the 45-70 BFR, then the gun has low pressure so I tried the .454 up to 55,000 psi with PB and shot wonderful groups. Plain old WD WW's. I got away from checks because of price and have learned you can get around them but not with softer lead. There is a point where you really need a check. Darn it, I can't tell you where that is! :veryconfu
Will barrels too short for the caliber spin up boolits? Can you shoot them fast enough? Can you hold heavy boolits in the brass under recoil with light, short guns? It is something to consider. That is the argument I have about a carry gun for bear. A 329PD S&W is just not at home with 300 to 350 gr boolits. The gun will work for you if you stay at 240 to 250 gr boolits.

[Southern Shooter]

I like the plain-base bullets for a couple of reasons. One, I like how they look and the nostalgia they bring to mind. Two, I don't have to deal with gas checks.

For, the record, I do have a gas-checked mold for this same weight bullet. But, I have not used it. And, I want to save it for the rare exception when the plain-base just won't do.
42910

For now, if this particular 360 grain, plain-base bullet, with a .37 meplat will only shoot straight at 1,000 FPS (measured 10 feet from the muzzle) from this particular 2.58" barrelled gun, then I will just accept that and keep using it as so.

I am assuming that this combo will be effective for short-distance (25 yards or less) self-defense anywhere in the lower 48 U.S. states?

Anyway, out of curiousity, I want to load this bullet up with the max of W296/H110 at 24.0 grains. I would like to see what will happen to the keyholing compared to those seen at 23.5 grains.

Thanks

[RevGeo]

Many years ago I bought an original trap door Springfield 45-70 at a gun show.
I bought a box of factory ammo with it so I'd have something to shoot while I got the reloading stuff together, plus to have some brass. I got a Lyman 420gr mould and made up some loads with 4759. Shot great. I decided to try the original load of 70gr of FF black powder. At 50 yards all of the bullets key holed. I messed with different alloys including pure lead but that rifle would always keyhole with the black powder. I tried a duplex load with 5gr of Bullseye under a caseload of FF black. The keyholing stopped. I ended up with the 4759 load. I never did figure out why that rifle key holed with 70gr of FF.
Key holing can be funny stuff.