Like I said, I'm into cast lead now. I've loaded some 9mm 124 gr SWCs and have been tinkering with the taper crimp so that they will pass the plunk test in the chamber of my barrel. I leave a slight rim of the bullet shank exposed,the case mouth just covering the lube ring. COAL about 1.12".

When I test them, they are just short of plunking to the full depth. I tightened the crimp several times but it doesn't seem to have an effect. If I push on the bullet very lightly, it will chamber fully and extract easily, but it feels like something 'soft' is keeping it from dropping that last fraction of an inch.

Question: Could the lead rim of the bullet be interfering with the last teeny bit of plunking???

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"He was kinda funny lookin'"

Plunk test? Plunk to full depth? What are we talking about? Fishing?

Try it with the shoulder flush.
If that plunks, you know it's the exposed shank.
There after, it's time to fire some to see if the rim really is a problem.

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it just needs more voltage

Yeah I had that issue with hornady LSWC in my .45. I made a dummy round and futzed with the OAL until they just plunked crisply. The ones that landed soft still performed fine but .45 is pretty forgiving. Careful with that crimp too much could cause some leading.

In my case that sharp shoulder was just touching the cone past the end of the chamber. I think that bullet shape lends itself to that happening.

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Trucks and guns.

I'm guessing at that OAL" the bullet isn't touching the rifling? When you drop the round in the chamber it should make a nice metal-metal sound. Spin the case around & it should be nice & smooth. If not try seating a little deeper. The other thing to look closely at, & it's my pet peeve when loading semi-auto lead rounds, is some lead shaves over the case mouth & makes it difficult to verify the plunk test. Sometimes I have to get a mini-flat tips screwdriver & run it around the case mouth to clear off the lead to verify it. Flaring the case a little more usually helps eliminate this problem when seating.

.

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Waiting for the break of day

Could also be an accumulation of bullet lube at the case mouth, giving the "soft" feeling.

Yes both of these also^^^^^

Especially if they still can be turned easily and they drop out without much resistance when you invert the barrel. Drove me nuts at first:P

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Trucks and guns.

I, too, agree.

WILDPIG

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I ain't from around here.

Take the barrel out of your semi auto pistol, or use a gauge.
When reloading for semi auto pistols the cartridge headspaces on the case mouth hitting the front rim of the chamber. You should be able to drop in a cartridge that 'plunks' right down to the bottom of the chamber and falls out when you turn the barrel/gauge down.

These reloads have functioned in my gun as a long as I minimize the the plunk deficiency. The force of the breech closing overcomes this little it of 'softness' and I don't want to overwork my extractor by having it have to forcefully pull the case from the chamber.

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"He was kinda funny lookin'"

This is the "plunk test" Assume you have given the case a correct taper crimp if does not drop in and out you need to seat the bullet a fraction more untill it does. Lead bullets are a bit larger in diameter so meaure your crimp.

Courtesy of Walkalong.

This topic comes up a lot, or should I say this question.
Quote:
Why won't my reloads chamber?
A short throat is sometimes the culprit. Too long an O.A.L. is sometimes the problem, even with barrels with average throats.

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Still Running Against the Wind

How much shoulder you got sticking out??

" How much shoulder you got sticking out?? " ..........

Enough to have a battery sit on top of it............


Sorry, I could not resist. Me bad.

....Knock it off!


LOL

It's hard to measure but it looks like I've got about .09" of rim sticking out past the case mouth.

My thumbnail is about .03" The COAL is now 1.12". The bullet could be pushed in a hundreth of an inch or so, about to where my Lyman book says at 1.11". The load is a little below midrange so I'm not worried about overpressure so I might go a little deeper. I think I'll make a batch and check 'em out.

This will work for my 124 gr. SWCs but I'll have to see how it works with the 147 gr. jobs.

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"He was kinda funny lookin'"

If you are not loading the max charge and the bullet does not pull out when you remove the round from the barrel it should be OK. Headspacing 45 ACP lead SWC touching the rifling for target work is common.
Reported to be more accurate as the case is in the same spot each time.

If you want a high velocity load, I would seat the bullet deeper.

As a general rule (like all "general rules" - limited utility) it is probably always best to keep the exposed lead of straight-sided cast bullets like #68 types and truncated-cones to not much beyond about 0.030" past the case mouth, or a bit less. Naturally, if that affects your cartridge OAL, like it can with some TC designs particularly in 9mm, you have to be mindful of it with your powder charge.

For accurate readings with your maximum ammunition gage (or barrel) always be sure to clean your cartridge with lighter fluid or some sort of solvent to remove all traces of lube before putting it in the gage. Traces of lube do tend to accumulate, so the gage has to be cleaned now and then too. The maximum ammunition gage is a better judge of the actual loaded cartridge case than your barrel, but only your barrel can pass judgment on bullet seating depth of all the different types of bullets. The gage does not deal with the length of your throat - only with the diameter of it.

Don't "over-do" the taper crimp. Turning in the case mouth a few thousandths of an inch is sufficient if your expander plug is sized correctly to do its job with the particular size of bullet you are using.

I reload for 4 semi-autos and I don't crimp any. I just use a taper crimp die to straighten out any flare in the case mouth. I would suggest you return your "crimp" to as light as possible and adjust the seating stem for "plunk". On two of my pistols, a SWC has only .010" of the shoulder showing...

As excellently described above the "Plunk Test" is a widely used, acceptable practice to determine proper bullet seating and "crimp", aka "deflaring". Much easier and for many better than just an OAL measurement...

FWIW, My 9mm Glock and CZ seem to have a shorter chamber than some of my other 9's. And those two did not care for certain shaped bullets near maximum OAL.

The OAL of a truncated cone 147 gr bullet that would fit fine in my other 9's, would ' hang-up' and not 'plunk test' in those two firearms.

The OAL of FMJ RN 147 gr didn't seem to matter.

The taper crimp was the same on all of them. The sharper shoulder on the TC 147's seemed to be the cause.

Hi-power rifle shooters / reloaders often use the bullet ogive to figure the length of ammo. The ogive of one bullet mfg. to another mfg. can / will be different.. If they used just OAL ,, one bullet maybe a few thousands off touching the rifling ,, another brand might be into the rifling.

rwsmith: You didn't say what guns this is for, not that it matters much I guess, but like old&slow was saying different guns have different leades & that can make a big difference.

All my 3rd Gens have .125"+ leades, except for the 9mms. My 3914 & my son's 5903 only have .100" leades. When I started loading 9mm for myself I found that some 9mms I had loaded for my other son's Ruger SR9c didn't pass the plunk test on my 3914 & I had to adjust the OAL" for that exact same bullet in my gun. Likewise, the 45ACP ammo I load that pass the plunk test in my 4516 & 845 don't even come close to passing in my Colt Series 70 Mk.IV which only has ~.040" leade.

I prefer to load all my autos to the greatest OAL" that still pass the plunk test in the intended gun without going over the max. OAL" for that cartridge, which is why I prefer using the barrel to check any new bullet styles I load.

. . . . . . . .

As far as headspacing a lead bullet of a semi-auto pistol on the rifling I don't see how that positions the case in the same spot each time? From my experience, bullets have little variations in their shape, especially lead bullets, which is why the measured OAL" changes slightly from seated round to seated round. Plus case lengths vary, within a set range. It would seem having the case mouth sit on the chamber's ledge every time would be the best way to position the case in the same place every time while adjusting the seating depth to position the bullet, rather than the bullet positioning the case. I know rifle target shooters do it (seat against the rifling) but what I've read it doesn't make a difference in pistols anyway.

.

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Waiting for the break of day

rwsmith;

When you get things to work, I will be interested on how the
OAL with those lead bullets work out. Since most lead is shot at
medium speeds I am curious if a short OAL or a long OAL shoots
better in your weapon.

With my plated bullets in a 9mm a short OAL with a fast powder
or a long OAL with lots of slow powder works at both ends of the
speed range, for me.

Good luck with that new lead bullet.

I'm loading for an S&W 5943, a third gen 9mm. I'm pretty sure the deeper seating will fix things. I'll get back to ya.

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"He was kinda funny lookin'"

Just loaded a batch of 124 gr SWC Missouri 9mm as before, but this time my COAL is 1.08" with just a bit of shank rim showing in front of the mouth and just enough crimp to deflare the case mouth. They plunk MUCH better. I have confidence these will function fine, but I'll be tweaking the next few batches. Range report next.

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"He was kinda funny lookin'"

Watch your powder charge.... The deeper you seat em, the lower you can drop your charge.

You were at what?? 3.5gr, and I don't recall you posting if it cycled or not??

I haven't tested them yet but I'm confident they will work as my pistol eats pretty much anything. The Lyman data (but not for the exact bullet I used) was 1.10" and I ended up at 1.08" which shouldn't cause an extreme 'excursion'.

I may be able to tweak the length a bit in the future, but this solved my problem of 'soft plunking' for now.

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"He was kinda funny lookin'"