Going crazy! Problem with a HG #275 clone!

[Swede 45]

Well, I´m going crazy!

I got a new mold, my first premium mold besides previous lee´s.
This is a MP for a 124 gr SWC in 9mm..
A beautiful mold of a quality that impresses me and a beauty to cast with..

Now, the thing that makes me go crazy! I can´t get those nice boolits to shoot straight!
Cant hit a 1x1meter paper at 25 meters rested.. the few that does are all over the paper and some goes sideways!
I´ve also tested some of the loads in my other 9mm´s with the same result!?

Facts: Alloy used is my spiced 20:1.
Actual xray test says 93.7%Pb, 4.96%Sn, 1.28%Sb and 0.07%Cu.
According to the calculator that would end up at about 11 Bhn aircooled.
I´ve used this alloy for other 9mm boolits and for stiffer 38spl and softer .357 mag loads before..

Gun: 9mm 1911 that normaly prints everything I feed it into 3-1 inch groups rested at said distance.
I´ve shot cast boolits in the gun before, both Lee´s 105gr SWC (but I have trouble with feeding due to short COL) and Lee´s 125gr RF. The 105gr shoots very nice, but feeds lousy, the 125gr feeds better but doesn´t shoot as great.

Barrel is slugged to 9.06mm = .3566
Tests are done with clean barrel and the loads doesn´t seem to lead.
Previously used boolits of other designs has been sized to .358 with good result.

Boolits: Boolits have rested for two weeks before use..
Boolits comes out at 131gr with this alloy, lubed with Randys Tac 1..
Boolits have been sized to both .358 and .357 ..same lousy result.
All boolits used in the test are weighted and in + - 0.5 grain from 131gr
Tapercrimp are soft but passes a presstest. (boolit dia + 2x case mouth thickness +.001 crimp.)
Pulled boolit shows no swaging.

Loads: I have used soft loads of Vithavouri powders N-310, N-320 and N-340
Sorted Norma cases and CCI Sp primers.
Velocity of tested charges has been very even, spreading just a few m/s from high to low.
COL is set to 26.5mm (1.043inch) due to the chamber / edge of the boolit for proper fit.
The few that hits paper are either randomly all over, or hits sideways.
2 strings of 5 shots was tested for each load with N-320 and N-340: sized..357 and .358

N310
sized .358
2.2gr, av. vel 250m/s (820f/s)
2.4gr, av. vel 260m/s (853f/s)
2.5gr, av. vel 269m/s (882f/s)
2.7gr, av. vel 278m/s (912f/s)
2.9gr, vel? chrono error.
3.1gr, vel? chrono error. Flat primers!

N320
3.2gr av. vel 294m/s (964f/s) .358
3.2gr av. vel 296m/s (971f/s) .357
3.5gr av. vel 313m/s (1026f/s) .358
3.5gr av. vel 306m/s (1003f/s) .357
3.7gr av. vel 316m/s (1036f/s) .358
3.7gr av. vel 315m/s (1033f/s) .357

N340
4.2gr av. vel 327m/s (1072f/s) .357
4.2gr av. vel 331m/s (1085f/s) .358
4.4gr av. vel 342m/s (1122f/s) .387
4.4gr av. vel 345m/s (1131f/s) .358

The ”best” result I got was 3 shots on paper, with two going sideways!
I also shot a known load at this session, and those printed a nice 2 inch group point of aim.

I was trying to figure out what was happening, and fired 3 shots from various distances, 5, 10,15,20 and 25meters, 15 shots in total with one of the loads that I had some extra of.
5 meters printed point of aim, clean holes. 10 meters, on target but opened up quite some. 15 meters was barely on paper, all over the place and two was showing tendency to keyhole. At 20 meter I only got one on paper and that went sideways. At 25, none on paper and I could see the impact in the sandberm behind.. way off in all directions!

The thing I can´t get my head around is why?
Why is this problem so extreme, and why does it occur with all different powders, sizes,velocities and in different guns when tried?
The 1911 shoots with cast of the same alloy and size and velocity span!
I have encountered keyholing before, but then usually in revos with solid WC with too soft loads that doesn´t stabilize (470f/s) or with HBWC pushed with a slow powder with to much muzzle push to blow the skirt or tip it over.. but this is new to me!?

Am I missing something?
(and there´s no use in pointing me to other powders, as Vitha is the only one available here.)

[Blammer]

first thing I'd try is water dropping them.

any leading in the barrel?

[Gemsbok405]

Had similar unstable performance with magna 123gr FPBB. As approached 1100 fps bullets were all over target (with Browning HP)! Both this magna and #275 clone seem very similar in profile, with exception of small SWC shoulder.

[44man]

Try changing hardness a little at a time all the way to WD WW metal or even harder.
The nine is near .44 mag pressures reaching to 32,000 CUP.
I have brought guns in using the same loads and changing alloys.

[Swede 45]

Blammer: No leading to speak of, fired close to 100 rounds in my test and barrel cleaned out easily.
I´ve made a test today with a selection of the previously used loads, but with waterdropped boolits. (had a bunch from the same casting session)
No luck, same result. I don´t know how hard those waterdropped ones are? Have no means of testing.

Gemsbock: I think the SWC shoulder could be a part of the problem. At 26.5mm COL the shoulder has contact with the rifling (short throat).Might be that it upsets the boolit in the start?
I just made a couple of rounds shorter, seating the boolits at 25.7mm with shoulder flush with the casemouth and testfired them of hand in my backyard. Best group so far! Will make a more in depth test of this COL..
44man: I have finally scored some lino to harden up alloys with.. WW and hard alloys are rare here.. all zink weights since a long time.
If the COL test doesn´t fix it, I´ll try harden up the alloy.

[44man]

Seating depth can help. Some time ago a friend brought me his rifle to find a load for. He did not have enough bullets or powder. I just changed seating depth with the same charges. Soon I had very tiny 100 yard groups with one depth. Sadly they did not fit the magazine but he did not care, he does not hunt and single shot was OK.
Your alloy will not harden much with WD. I have the LBT hardness tester and can measure each.
I still do not depend on BHN numbers since I can add stereo lead to WW metal and get a lower BHN but they are still tougher and shoot better. You can make a few thousand alloys of the same BHN and every one will shoot different.
There is no standard for how a boolit holds up so if someone says "I use 14 BHN" what does that mean? The alloy might be twice as tough as another 14 BHN boolit!
To recover boolits undamaged by impact is where I see what goes on.

[Swede 45]

I usually play around with seating depth both in rifles and handgun loads to tweak accuracy when I find a load that shoots decent.. problem here is that I have no accuracy to start with! :???:
I´m convinced that something happens during the travel down the barrel that causes the boolit to loose stability and go buzzing downrange in all directions, but straight !

Cant be the velocity, since I´ve covered quite some span.. cant be the powder as I´ve tried several.. cant be the fit as barrel is slugged and both .357 and .358 are tested..
Might be that the throat contact causes the boolit to act weird? Could also be that boolits somehow climbs the rifling and doesnt gain the twist to stabilize?
More tests will tell.. or might make me jump of a cliff! [smilie=b:

And I understand that hardness is just a number.. and that different alloy compositions can share the same Bhn but have totaly different characters depending on the actual mix..

[Gemsbok405]

[QUOTE
Gemsbock: I think the SWC shoulder could be a part of the problem. At 26.5mm COL the shoulder has contact with the rifling (short throat).Might be that it upsets the boolit in the start?
I just made a couple of rounds shorter, seating the boolits at 25.7mm with shoulder flush with the casemouth and testfired them of hand in my backyard. Best group so far! Will make a more in depth test of this COL..
[/QUOTE]

I would not be surprised that the shorter COL is creating a bit of freebore...and reducing peak pressure. I have found seating so the SWC shoulder is just on the rifling gives good accuracy, but is very lube dependant. The velocity measures would be very interesting between the two seating depths.

[44man]

I have not been lucky with a SWC since the shoulder gets mashed at the cone with an off center start.
But a nine is an auto with no forcing cone. Different from a revolver so i just don't know.

[runfiverun]

re-look at your alloy.
you have antimony in it.
the tin and antimony form a specific alloy inside the lead.
the leftover tin forms a separate matrix.

anyway that ain't your problem so much as the sideways boolits are indicating.
you have key holing this is caused by instability.
instability is caused by 2 things.
you are not gripping the rifling, or you are not spinning them fast enough.

[44man]

re-look at your alloy.
you have antimony in it.
the tin and antimony form a specific alloy inside the lead.
the leftover tin forms a separate matrix.

anyway that ain't your problem so much as the sideways boolits are indicating.
you have key holing this is caused by instability.
instability is caused by 2 things.
you are not gripping the rifling, or you are not spinning them fast enough.
Glad you came in with spin and skid. Related to soft lead that skids.

[Swede 45]

Thanks guys for the input..
I made an experiment today and loaded up a few rounds with the SWC shoulder seated flush with the casemouth and just testfired them in my backyard.. best result so far!
I have cooked up a strange theory about that the shoulder of the boolit strikes the headspace ledge of the chamber upon chambering and shaves of a portion.. therefore an uneven resistance/friction when fired and contacts the rifling.. that causes the boolit to cant slightly, swaging it down and forcing it through the barrel of center? Thus the instability?! Just a home cooked theory by a simple idiot! ;-)

Other hints I´ve got are of similar thoughts, but more towards the sizing punch not centering the boolits in the sizerdie, or the seating stem not centering while seating the boolit.
A new batch are loaded and I´ll go to the range tomorrow and see if the shorter OAL might cure the problem?
Otherwise, back to the thinktank.. :-?

I just got 70kg of printers lead with 12% antimony and 4% tin delivered to my door.. so if I have to spice up my alloy to a harder level, that might come in handy! Animony rich alloys are super rare and hard to find here.. so that was a score !! :D
I´ll keep you updated!

[Swede 45]

Well, I´m back from another rangetest.. and I tried the shorter OAL theory.. no luck! turned out to be just a homecooked theory by an idiot! :mrgreen:
Also tried a harder crimp of the max OAL cartridges as someone was suggesting as my careful crimp beeing the problem.. no change in performance.

Next step is to se if everything alignes right in the sizer and seater.. and mix up another alloy..

[popper]

Sized 357-8 so what do they measure? Your alloy won't HT worth a darn. Too much Sn, you need 30# lino to 10 of your 20:1 to get Sb=Sn. You need ~3% Sb AC. If you have pure, I'd mix with the lino, for get your 20:1. I only use tin if it comes in the alloy I buy, i.e. - you DON'T really need ANY.

[tja6435]

As the boolits are cast, have you checked to see if they are round?

[Swede 45]

yes they are..