mould halves seems to be mis-aligned, to what "tolerance" is this normal?

[WouterNL]

Hello,


I'm quite new to casting liquid lead, and at this moment I have two Lee moulds and one rcbs mould.

I'm a little bit concerned about the rcbs mould. It looks like that the boolits which are coming out of this mould are not perfectly round. The mould-cavities are not perfectly aligned (boolits out of the both cavities have the same problem).

At the picture below you will see two boolits which I made at the same run.
The one on the left is not sized, the one on the right is sized with a lee .308 sizer.
The mould is a : RCBS-30-150-FN



It's clearly visible at the sized boolit that at the left side of the "line" lead is scraped away, during sizing, at the right side of the line it isn't


Below there is a photo of the back-side of the mould, maybe i'm wrong, but the mould-halves seems to be lined up correctly:






I don't have this "mis-alignment-issue" with my lee-moulds. So I was wondering if this is normal or not?

maybe someone knows?


Best regards;

Wouter

[williamwaco]

Molds rarely cast "round" bullets but if I read your drawing correctly yours are out .3105 - .3075 = .003

I think that is too much. I usually see .0005 t0 .0015.

Hold that closed mold up to a strong light source from every angle and every side and see if you can see light shining through the crack

[texassako]

Take a look at the top of the mold to see and feel if the 2 cavity halves line up. I would also check the alignment pins. They could allow the mold halves to slide side to side a little if not set right. Check it off the handles to see if you can move the blocks separately while the mold is closed. The final test is how does it shoot? It may not even be an issue.

[littlejack]

Wouter:
Welcome to the CastBoolits sir.
If it is an alignment issue, and cannot be corrected with the alignment pins, you cam probably take
most of that out by "beagling". And you ask, What the he!! is beagling? Putting aluminum tape on the
inside of one side of the mold block. This spaces out the blocks to enlarge the boolit cast.
The ideal situation is to have the boolit "small" 90* from the part line. I have a Lachmiller 454190 that
casts small that way. I taped it and it works great.
I believe that you will be able to make your boolits acceptable by doing this.
If you do not have any tape, PM me your address, and I will send you some.
Regards
Jack

[Le Loup Solitaire]

If the bullet works well for you then stick with it. If any of the previous suggestions do not remedy the situation and you continue to have concerns then pack the blocks up and send them back to RCBS with a note of explanation and they will send you a replacement. They have an iron clad guarantee. LLS

[WouterNL]

Thanks for the replies!


After looking very well to the closed mould I don't see sings of light coming trough the crack.

When the block is closed i can't move the mouldhalves, the alignment-pins are sitting rock-solid in the alignment-pin-holes.... Now while typing this the idea comes up: when the holes (or the pins) are slightly off-center... then it's causing the problem.

Littlejack, thanks you for offering to send a piece of alu-tape, but i have some of that in my shed. For this mould I don't think this is the solution, but maybe i can use this idea somewhere in the future.


Yesterday I made a few rounds which i'm going to shoot out of the k31... bottomline is: shooting is the proof of the mould.....

I will give an update about the result.

[Longone]

Also make sure you are using the proper alloy, RCBS calls for Linotype in their rifle moulds. If you aren't using Lino it might just be shrinkage that you are experiencing.

Longone

[kungfustyle]

If you cast with the mold too hot you can get out of round as well.

[littlejack]

You are welcome sir.

[Cap'n Morgan]

Don't fret it. Since the mold halves are offset symmetrically, the boolit it will still be in balance. Size, shoot and be happy...

[geargnasher]

Definitely out of alignment more than I wold like to see, but shoot them first and see. I have corrected a few Lyman moulds that had the same issue by some very careful filing of pins and peening around one side of the alignment pin socket hole to effectively shift the blocks back into alignment. This only works for moulds that have the cavities correctly cut to depth, which often they do not if the blocks are shifted. "Beagling" or peening several dimples on the block faces to separate them the required amount and then re-adjusting the pin depth to snug the alignment will make them cast round AND aligned if this is the case. Or, if it proves to be a problem, return the mould to RCBS or where you purchased it for an exchange. If you modify it you pretty much void the warranty.

Gear

[WouterNL]

After reading Cap'n Morgan's reply I felt there is a chance that the mis-alignment maybe isn't a problem. As far I can see the boolits are symetrical

At the pictures below you will see the result of my shooting this evening with some cartridges which I put together:

The targets at the both pictures are shot with 16grain of alliant 2400 powder in the case, the boolits were seated a little bit off the lands. The rifle was fitted with a 10x mag. scope and supported during shooting. The distance to targets was 100 meter (indoor range).

The only difference was the used boolit and the lube.
The target of the first picture is shot with boolits out of a LEE-CTL-312-160 mould, those were first tumble-lubed with lee-alox, then sized .309" and tumble-lubed again.

The target at the second picture is shot with:
Boolits out of the RCBS-a-symetrical- mould (rcbs-30-150-fn), first tumble-lubed with lee-alox, then sized to .309" and pan-lubed with a 50/50 mix of beeswax and a partially hydrogenated vegetable fat).






At this moment, the a-symetrical boolits are a little bit better then the "good ones".
My concerns about the boolit-quality of this mould are gone...


The over-all quality of the cartridges (and my shooting-abilities) can be better I think.
can I do much wrong by making the overall-length of the cartridge a bit longer? (that the boolits are just seated against/slightly "in" the lands)?


Wouter

[ohland]

Looking at the targets, I don't see any noticeable tipping, so the bullets seem to be stabilizing.

The top target looks like some stringing? Bottom target looks like a group. A wee bit large, but a group.

You showed a gas-check bullet up top, but I didn't see a mention of whether you used a GC.

What velocity (in fps!) were you expecting?

My Dad has been having fun with a 32-40 Winchester, which -supposedly- should use a .321 groove. Our range session yesterday suggests a sized diameter of .323 may be better. For more fun, shooting hard, undersized bullets can lead to leading. How's your bore look?

Some things I would consider (trying to keep the panic down):

2400 is a pistol powder, it should be fast enough to "bump up" a bullet some. Might try sizing to .310? No ideal of how the cases look after you fire, or how loud it is... Might increase a half grain and see if the group tightens. A gas check is better if you don't have a perfect size die, since a plain base bullet (that has too small of a diameter) is a little more apt to have gas-blowby upon firing.

Talk some more to us and don't be a stranger.

PS. Could always ask RCBS about returning the mold. They have been pretty good to me.

[Buckshot]

...........If I bought a new RCBS mould and it's blocks were offset .003" I'd be sending it back to them along with a couple of the slugs and an explanation. I have several of their moulds but years back I bought their 7mm-168 mould and while the blocks were not 'offset' they had not been closed completely on the cherry when they cut the cavities. The boolit was like a football in cross section and was grossly undersize perpendicular to the parting line.

I sent it back to RCBS and got it back in about a week. It was a new mould but had the same exact problem, so I suppose they had a bad batch. This time I included a couple cast slugs when I sent it back to them. It wasn't long and I had another mould from them, and this one included 4 slugs they'd cast and they were perfection. If you can wiggle the block halves against each other while holding them tightly together then you have a problem you might be able to rectify by driving the alignment pins out a bit, and just a little bit is all that should be required on a new mould.

Even though you have a cast iron mould you still need to exercise a bit of care when closing them together as the alignment pins banging into the perimeter of the alignment pin holes won't do them a bit of good.



This is an old Lyman SC mould and both pin holes were badly beat up like this. As a result the blocks literally rattled against each other.



Across the parting line they mic'd .3592" x .3618" which is just shy of .003" which is simply too much.

...............Buckshot

[WouterNL]

Gaschecks are used.
The velocity unknown, but i will take the chrony to the range some day.

The cases looked good (and clean) after firing, not cracked or primer flattened. And the cases extracted easily out of the K31 (straight pull).

Unfortunatuly I can't size down to .310 but i have a .311 sizer.
The next time I will use .311"sized boolits with GC.
Instead of 16 grain I make one serie of cartridges with 17grain of powder and one serie with 18grain powder.

I contacted RCBS about the issue, but they are applying their warranty-rules strictly. Because I'm not the original buyer of the mould (I bought the mould from a guy who sold the casting-stuff of a friend of his which has died) RCBS informed me that they can't help me out with this.

When I have the mould-halves closed to eachother, then i can (when I apply some "controlled force") notice a sligthly movement between the halves.
But I can't tell at this moment (i'm not sure) if this is the situation which Buckshot is explaining.

[WouterNL]

small update:

the above info was about boolits shot with my Swiss K31.
The mis-aligned rcbs boolits do not perform very well in this rifle.
The boolits out of my Lee CTL-312-160 mould are also not the way to go for me.
But, when I use boolits out of a LeeC309-170-F mould, then the result is ok for me, now i have to test with a little variation in powder-amount.
It's difficult for me to quantify the difference in performance of those boolits, but this is how it is.


Besides in the K31 i have tried those rcbs boolits in a '78 build Winchester 94 which i inherited (30-30).
The strange thing is, the Lee 170grain flatnoses did perform not well, but the misaligned rcbs 150gn flatnosed are performing very ok.
Both shot with 16 grain Alliant 2400 powder. I tried only at 50m (I'm shooting the K31 only at 100m

For now I'm going to test further with the rcbs-boolits in the win94, the to-test parameters are: amount of powder, type of lead (first testresults indicate that my rifle a harder type of lead preferres).

Now I shot all with gascheck, maybe later I will try without.


Summarizing:For now I learned via this topic:
The mis-alignment of the boolits out of this mould is more than I should have to accept, unfortunately I'm not the first-buyer of the mould, so I don't have guarantee from the producer.
But finally the target tells the performance, this mould is a keeper for me for the win94!

Thank you all for replying in this topic and giving me directions to help me out with this, I learned a few things I didn't know, for now I didn't apply all the ideas (for example; beageling), but in future maybe.



Best regards;
Wouter