Strange chamber leading while shooting cast

The Hackmaster

The Hackmaster

CGN Regular
Rating - 100%
29   0   0
Well I'm back again and still trying to zero in on a good alloy for hunting bullets. I started a thread a couple below this one asking the more knowledgeable folks here what they would recommend and used that info as a starting point.

I went to the range a couple of days ago with my first batch of cast and two rifles borrowed from friends for testing. I had with me a Marlin 1895 in 444 Marlin and a Marlin 336 in 30-30.

The molds used were an NOE copy of the ranch dog 311-165 TL with gas check, and the 444 marlin was cast from an accurate molds 43-300B. Both bullets are tumble lube designs, both powder coated with eastwood tool blue, both gas checked, both cast from 20-1 alloy. They tested about 7.8 BNH with the Lee hardness tester. The 444 bullets were sized to .433 and the 30-30 bullets were sized at .312, as the marlin micro-groove bore slugs at about .3108''. The 444 bullets weigh in at 300 grains, the 30-30 weigh 170 lubed and checked.

I settled on 20-1 for it's expansion properties on game, however I realize it might be way too soft. With the powder coat and gas check I was hoping too expand the useful envelope of these bullets.I had no leading in the barrels of either rifle.

That being said, the 30-30 didn't group particularly well. About 4'' at 50 yards, and since its scoped and I had a good rest, I think the accuracy issue must be with my bullets. It didn't string in any direction, I just got repeatibly bad groups. For a short range hunting rifle, I can live with 3-4'' groups at 100 yards but not 50. The load was 30 grains of H335, case neck flared with a lyman M die and all charges weighed by hand. I fired a couple of other groups with different charges but this one preformed the best.

The 444 grouped amazingly well. It's one of the newer ones with the ballard rifled barrel and seems to take to cast lead very well. However, as you can see from the pictures (or maybe can't, I hope the links work) all the fired cases had a ring of lead and powder coat at the case mouth. This ring is not on the case but just in front of it. I took a chamber cast (picture #2) and I can't figure out why the bullet is being shaved like that. The bore measured close to .432 from the cast, so a .433 bullet should be just what the doctor ordered. It just doesn't explain the shaved lead on the neck. Load was 54 grains of H335.

So if you have read this entire wall of text thanks for staying with me! My question to the more knowledgable are:

-What could be causing the bad groups in the 30-30? Possibly the too soft alloy?

-What could be causing the shaved lead in the 444? I'm worried if it builds up too much it could affect function.

-Is 20-1 a little too soft in general for what I'm trying to accomplish? would somthing like Lyman #2 be a better option for a hunting bullet?


Thanks again for putting up with those like me who are new to the casting game!



 
With the .444, your brass might be too short, causing the bullet to start expanding in the leade area, then being swaged down to the bore, cutting lead rings. These lead rings will eventually enter the bore and cause leading there too.
 
ryan said:
With the .444, your brass might be too short, causing the bullet to start expanding in the leade area, then being swaged down to the bore, cutting lead rings. These lead rings will eventually enter the bore and cause leading there too.
Click to expand...

Somthing weird is going on there anyways. The lead rings are almost exactly 0.050'' tall and 0.010 thick and fairly even all the way around. The brass is only 2.215 instead of 2.225 so it is too short but not enough to explain it either.
 
.30/30.

Perhaps, your powder is a little too fast for the bullet. I have good luck with 748 in the .30/30. On the relative burning rate chart, H335 is at 113 and WW748 is at 137. In the second edition of the Lee loading manual, Richard Lee has a very interesting theory on bullet strength and the amount of pressure it can handle without deforming. Is your case length and therefore crimp, consistent? If you have a mild crimp, follow up shots and magazine spring pressure may push the bullet deeper into the case, causing erratic results. If you single loaded, in this case, it won't be an issue. Personally, I would use a larger bullet, at least .313 and even .314 if you can chamber a cartridge with a fatter bullet. I don't like micro-groove barrels and never owned a centre fire one, but my reading indicates that good accuracy can be had with larger bullets.

.444
Again, I'd like a larger bullet, but if you have the accuracy, great.
How is your case length? It looks like your cases might be short for the chamber. The chamber cast shows different texture where the last bit of case near its mouth would be. Could the chamber be too long, and bullet jacket material (The Tool Blue coat) may be filling the extra space in the chamber. If your chamber is too long, trim your cases only enough to keep them square and hope they lengthen with use. Perhaps, have a long range session, to see how many rounds it takes before any fouling becomes an issue. I'd wager that it wouldn't interfere with a hunting trip and the relatively few rounds that would be expended.
 
Looking at the chamber design on the 444, I see a very short throat, and an abrupt transition from chamber to rifling, that can most definitely cause those lead rings. If you can stretch your brass a bit, that might help, but some chambers do not work well with cast bullets.
 
7.8 BNH
is too soft

are you flaring your case necks ?

What is your load Data ?

3030 is prob too Fast ( could also be too soft )

ww with a bit of lead free solder added Air cooled should be a good mix ..... even water dropped should still be ok ....
 
Don't know what to say. Chrony readings would be nice as the is a velocity threshold depending on bullet hardness.

This is the fun part, figuring out what your gun likes.

If you have the Lee hardness tester you also got the chart which correlates the velocity to hardness..

Most of my bullets are straight WW + 3% pewter. My 45-70 is 50/50 WW to pure +3% pewter.

As for sizing, all my .308 get sized to .309. My first cast reloads were random picked charge between min and max. Bullet was water quenched and alox lubed. Pic below was shot at about 65 yards off hand.

Get a chrony, Im thinking that will tell you the story; too fast for the bullet hardness.

1tMtIXX.jpg
 
just having some fun said:
7.8 BNH
is too soft

are you flaring your case necks ?

What is your load Data ?
Click to expand...

Case necks are flared in both calibers. I use a Lyman M die on the 30-30 and the 444 die set comes with one. I flare the cases enough that I can get the top of the gas check into the case by hand to make sure the cases are open enough that I can seat the bullet without shaving off powder coat.

30-30 load is cci200 primer with 30 grains H335. The hornady 7th edition puts this at 1850ish FPS with a jacketed bullet, tested using a winchester model 94 with the same barrel length as the marlin 336.

444 load is cci200 primer, 54 grains H335 ( I have a lot of it ) This is over max for jacketed according to the Hornady manual, but shows no pressure signs and SHOULD be about 2100 FPS.

I also suspect 7.8 BNH is too soft.
 
Last edited:
yomomma said:
Don't know what to say. Chrony readings would be nice as the is a velocity threshold depending on bullet hardness.


If you have the Lee hardness tester you also got the chart which correlates the velocity to hardness..

Most of my bullets are straight WW + 3% pewter. My 45-70 is 50/50 WW to pure +3% pewter.


Get a chrony, Im thinking that will tell you the story; too fast for the bullet hardness.
Click to expand...

The frustrating part is I all ready have a chrony, but the way my range is set up I have no access to the front of the firing line when the range is live. A labradar would be nice but at $700+ is not in the budget right now.

According to the chart I got with the test kit, I am WELL outside what the alloy can support. It lists max pressure for 8 BNH as 10,261 PSI. Both the 444 and 30-30 SAAMI pressure limits are 42,000 PSI and my math tells me I am at 30,000-38,000. I was hoping that between a gas check and the powder coat I could shoot a softer bullet for hunting but it doesn't appear that I can stretch things that far. Also, if the remains of what i dug out of the backstop are any indication, these might be too soft for hunting too. I know dirt is a poor analogy for critter, but the bullets I recovered from the backstop were basically nothing but gas check and one or two tumble lube grooves with some blue powder coat. At least I know the gas check is surviving the flight.

Good shooting by the way. I'm useless offhand.
 
Last edited:
Try your alloy into several water jugs to see how it expands or if it fragments (water jugs are a somewhat better test medium than dirt). Your slugs at the correct hardness should have a nice mushroom to them similar to a soft point or hollow point slug. I suspect you knew that, you seem to have done a lot of homework.
 
Looking at your cases and the consistency of the leading, potentially too much crimp for the bullet design/hardness causing the case to shave some lead off the bullet as it swages out the crimp and depositing it in the eddy at the mouth of the case before it hits the throat proper. Being a tumble lube design and a soft bullet I can easily see the first ridge peeling off on the crimp and then getting deposited.
 
ryan said:
Looking at the chamber design on the 444, I see a very short throat, and an abrupt transition from chamber to rifling, that can most definitely cause those lead rings. If you can stretch your brass a bit, that might help, but some chambers do not work well with cast bullets.
Click to expand...

I agree with Ryan. The almost non-existent taper to the throat will be the culprit here with the sharp edge stripping the PC from the slug. Do you PC after sizing (some folks do), that will add to your troubles in this case, probably add 1.5 thou to your bullet dia. I size everything before coating & then afterwards, have shot some very soft PC'ed slugs and never had what you show in the photo's

Personally I have only seen this one time before and that is with an original RB barrel re-chambered into 50-90. The new chamber had a very sharp transition from case mouth to rifling lead & shaved leads as yours does ( long before PC'ing was a thing).
 
The Hackmaster said:
The frustrating part is I all ready have a chrony, but the way my range is set up I have no access to the front of the firing line when the range is live. A labradar would be nice but at $700+ is not in the budget right now.

According to the chart I got with the test kit, I am WELL outside what the alloy can support. It lists max pressure for 8 BNH as 10,261 PSI. Both the 444 and 30-30 SAAMI pressure limits are 42,000 PSI and my math tells me I am at 30,000-38,000. I was hoping that between a gas check and the powder coat I could shoot a softer bullet for hunting but it doesn't appear that I can stretch things that far. Also, if the remains of what i dug out of the backstop are any indication, these might be too soft for hunting too. I know dirt is a poor analogy for critter, but the bullets I recovered from the backstop were basically nothing but gas check and one or two tumble lube grooves with some blue powder coat. At least I know the gas check is surviving the flight.

Good shooting by the way. I'm useless offhand.
Click to expand...

Try a magnetospeed chronograph. Theyre cheap and work great
 
fingers284 said:
I agree with Ryan. The almost non-existent taper to the throat will be the culprit here with the sharp edge stripping the PC from the slug. Do you PC after sizing?

Personally I have only seen this one time before and that is with an original RB barrel re-chambered into 50-90. The new chamber had a very sharp transition from case mouth to rifling lead & shaved leads as yours does ( long before PC'ing was a thing).
Click to expand...

The powder coat goes on before sizing. I have a tough time getting the bullets through the die if I don't have some kind of lube on them. I just got some rotometals super hard today so the next step is to try some homebrewed Lyman #2. If that sharp shoulder becomes a persistant problem it might be time for a trip to the gunsmith.
 
Well I got back from the range today and I have the 444 lead rings solved! I cast up some of the exact same 300 grain projectiles except this time I made them from Lyman #2 and measured them at 14.5 BNH. All trace of leading is gone, and it shoots 2 inch groups at 100 with irons. I figure the 20-1 alloy was soft enough at 7.8 BNH to slug up in the very start of the chamber. The harder alloy seems to stop that.

The Marlin 336 in 30-30 is still a turd though. It is still shooting 6-7'' groups at 100 yards. I know the newer remlins are better than this so I may have to investigate the rifle instead of the ammunition.
 
The Hackmaster said:
Somthing weird is going on there anyways. The lead rings are almost exactly 0.050'' tall and 0.010 thick and fairly even all the way around. The brass is only 2.215 instead of 2.225 so it is too short but not enough to explain it either.
Click to expand...

That looks like powder coat residue. What ever you want to call that stuff, it is thermo-plastic. It melts under heat and pressure. In a gun, you have both. Unlike plain bullet lube, it also burns and forms an ash mixed with burnt and unburnt powder, and lead. I quit using powder coated bullets after the second try (and I was using factory ones) Reloading issues, size issues, and dirty, dirty guns. Try some un coated bullets with standard lube and compare results.
 
My experiences with PC'd slugs is the exact opposite, after hundreds of shots fired with a dozen or more rifles ( some of them with old BP corrosion), I have yet to see even a hint of a "skid mark" in a bore that is so common with wax lubed slugs...the un-burnt powder thing certainly isn't a PC caused anomaly. I get un-burnt powder at times with certain powders ( especially the 5744 that I am switching to replace my dwindling 4759 supply).
 
You must log in or register to reply here.
Back
Top Bottom