Bands Vary

[ColColt]

I don't think this matters but thought I'd ask anyway. I received a mould today and in my specifications ask for it to be .459". The only portion of the bullet that's .459" is the base. The rest of the bands are .4577-458". I know the bullet will get bumped up but I've gotten moulds from this same person and all bands have been .459-.460". Forget it and just shoot?

[Sweetpea]

Custom mould maker?

Did you specify the alloy you were to be using?

[ColColt]

I did-1:20. Yes, it was a custom job.

[Sweetpea]

I'd contact the maker first, see what he has to say.

[DR Owl Creek]

A buddy of mine recently bought a high end custom mold spec'd at .461" for one of his '74 Sharps. Even though he's been casting for 30+ years, he had a similar problem with only the base band coming out at the spec'd diameter, with all the others being smaller. After a lot of frustration, I believe he said he had to change the temperature of his alloy and preheat the mold before he solved the problem.

He doesn't post on this forum very often, but I'll try to get him to post a more specific response about what he had to do to make it work for him.

Dave

[ColColt]

It's difficult to measure each band as a mic is going to measure two together. I took my calipers and measured each band and found the base and the band above it was .459" but all others were smaller, to include the drive band. From an accuracy standpoint, I don't know that all of this matters or not. I did expect, however, all bands to be the same.

[RobS]

Are you bottom pouring or ladle pouring. Sometimes from a bottom pour pot it helps to swirl the alloy into the mold by directing the edge of the pot's lead stream on the sprue plate's angled part of the pour hole (hope that makes sense). If you've tried this and other means such as adjusting temp. etc then I would simply contact the mold maker as I don't believe any of them will have a problem making things right.

[ColColt]

With these large cavity(530+ gr) moulds I use a ladle, usually around 750 degrees. I've found the consistency of weight and sharpness of bands work best with the ladle pour method.

[RobS]

Ladle pouring with big ones keeps the heat on the mold so that's good. I would contact the mold maker and go from there since the mold isn't dropping boolits the way you expected.

[dualsport]

Maybe they will shoot good. Only one way to find out.

[ColColt]

I've got an email into him to see what he thinks. It may make little difference but I'll be at the range this week and we'll see what transpires.

[TXGunNut]

Possibly a mold temp or break-in issue, be interesting to hear from the maker but proof's in the pudding. Hope it works out for you.

[Enyaw]

Could be air in the mould. Keep the laddle spout on the mould a little longer so the weight drives out the air. Turn the mould sideways to meet the spout and then turn it right side up with the laddle spout tight to the mould few extra seconds.

Make sure the alloy is mixed well periodically.

If the mould cavity is made to the right specs. it may be the air vents are not right.

Clean the mould with gas and then de-natured alcohol and a soft brush and then do it two more times. A soft carding brush works good. Brownells sells them. Small like a tooth brush with fine stainless steel wire bristles.

Might work to remove varnish type stuff from oil/grease left on the mould.

Might try a lighter grip on the mould handles too.

Might try upping the alloy temperature.

Night try running the mould a lil slower so it's temp stays a little lower.

[ColColt]

Those are good suggestions but I checked the dimensions of the sample bullet sent with the mould and it measured the same as the ones I cast. Again, I don't know if this is being nit picky or not, just out of the ordinary for his moulds.

[Enyaw]

If yer being nit-picky then that goes along with the habit of rifles to be nit-picky bout the bullet size they want/like.

In the beginning you mention that you,"know the bullet will bump up". Using the Holy Black or smokeless?

Black powder bumps up lead alloy bullets more than smokeless powder will. As I understand it the smokeless isn't a real good "bumper upper".

Anyway....you should send the mould back fer one that fits yer specs.

[ColColt]

I received an email back from him and was told not to worry about the small undersizing but, he would check it out if I wanted.

[Wayne Smith]

Hold on to that promise and shoot a few and get back to us.

[ColColt]

I hope to get out to the range this week. I was going today but have a dentist appointment and that sort of stymies my range trip. I just felt it odd that the last mould I got from him was a tad over sized at .461" instead of the .459" I specified and this one was the opposite. I had no problem with the .461" mould as I use a sizer anyway and not being over .002" I felt that wouldn't affect accuracy. I don't like sizing more than that, however. I suppose it's difficult to get each band the same as the others and perhaps .001" difference won't mean a thing.

[country gent]

I would shoot some and see what they do, et the bullet rifle combination decide if its right. With Black powder loads it should bump up easily to a perfect fit. Are you gravity pouring into the mould or pressure pouring from the ladle? If its a vented sprue plate on the mould try pouring the full ladle into the mould letting the excess run from the vent back into the pot. This givees me very consistant bullets as it keeps the bullets hot the longest and beter fill out and gas release.

[ColColt]

I use a ladle(Lyman) with the larger bullets, single cavity such as this one. I tip the mould to line up with the ladle, turn it over and mentally let it sit there three seconds before leaving a sprue on the mould.

I'm shooting 62-65 gr of black with this type of bullet so it should bump up nicely. Still, I wish all bands had been the same.

[ColColt]

Went to the range today and it seems my slight concerns were to be unfounded. The 540 gr Creedmoor bullet gave me the best groups of the day. I'm surprised they did as it was 42 degrees and I had been out in it about two hours when I shot these groups. My feet felt numb as did my fingers but in between warmups in the car I managed to get some decent groups. Both Swiss and Old Enysford did well.

http://i180.photobucket.com/albums/x220/ColColt/My%20Targets/_1DF3177a_zps72e51d9f.jpg (http://s180.photobucket.com/user/ColColt/media/My%20Targets/_1DF3177a_zps72e51d9f.jpg.html)
http://i180.photobucket.com/albums/x220/ColColt/My%20Targets/_1DF3178a_zpsf5c6c9a4.jpg (http://s180.photobucket.com/user/ColColt/media/My%20Targets/_1DF3178a_zpsf5c6c9a4.jpg.html)

Olde Ensyford did well with the Lyman 457125 as well. It may be my go to powder hence forth.

http://i180.photobucket.com/albums/x220/ColColt/My%20Targets/_1DF3176a_zps0a108f53.jpg (http://s180.photobucket.com/user/ColColt/media/My%20Targets/_1DF3176a_zps0a108f53.jpg.html)

[RobS]

Not bad at all............even if you were half numb.

[Enyaw]

Not bad groups there Hombre!
I have had the same problem with differing band diameters in a new mould. Things improved when I upped the heat to the alloy and the mould. I was trying to see if I could run the alloy cooler than usual. Didn'twork well. I had the right size bands all but the one next to the sprue plate. It would be differenin by .001-.002 inch. The others right on .461 as they should be. When I upped the temp the bottom band got better and right on or .001 under the expected .461 like the sample bullet that came with the mould.
Weird thing....upping the temp of alloy and mould could give some of the bullets bands(not the band next to the sprue plate) up to .462 size. The sample bullet that came with the mould had all bands the same at .461 using 1-20 alloy.

I'm using up an alloy that was initially 96% lead,4% antimony,2% tin and now with extra lead added this time around. That alloy with the extra lead to soften it gave better groups being softer.

I'm headed towards the 1-20 alloy since this alloy I've had with the danged antimony is just about gone. Don't care much fer the antimony.

Anywhoooo......Might try an alloy that is softer. 1-30 or 1-40 might bump up better. Watch for leading that could indicate the bullets bump up too much and get too tight.

If it'll give a good diameter (.001 or .002 over groove diameter or right at groove diameter) size so all driving bands are the same. Try er out.

I don't like to rely on obstuation of the bullet to make it fit since I'm of the mind set that something like obstuation isn't going to be as consistant as some believe it is.
I believe an Hombre can size right at groove diameter and end up with a overly tight bullet because of the alloy and obstuation of it.

How do you spell that danged word? Obsturation? Obstuation? Oblogerinzitationalistic? Bumpup? Plumpit?

[ColColt]

It's called obturation. There was no leading with this 1:20 alloy I always use and the miniscule difference of three bands made absolutely no difference. I feel rather sure those groups could have been even better had I used a scope or had 20 year old eyes and wasn't freezing.

[Enyaw]

Obturation. I gotta write that down somewhere. Thanks Colcolt.

I agree bout the freezing and the use of a scope woukd no doubt give better groups.

I'd like to have a scope like the Malcolm types MVA sells. Of course then I'd have to make up different reasons why I'm not shootin better. :veryconfu

I have learned to figure out what part of the fuzzy stuff to aim with. I'd be satisfied with the kind of groups you attained. Hope you get that consistantly.

Who knows.....maybe next outing you'llfind the group shrinks even more when the bullet settles down more on it's axis. Half the group at twice the distance would be nice.

Less of a group even 50 yards more would be cool. Minute of ground hog at 300 yards would be alright.
:shock:
Glad things worked out fer ya Hombre. Now I might figure that if my mould has a bottom band .001 less than the rest it may be alright.

[Wayne Smith]

Glad it worked out for you. I suspected it would.