Sizing for 44 mag

[heavyd]

I want to load my Ruger Super Blackhawk in 44 mag for precision and hunting. Just slugged the barrel and to my surprise the slug miked at .4317. My current sizing die is .430. Do I need to have lathesmith open my sizing die to .432?

Other problem is, my Lyman 429421 mold drops boolits anywhere from .4310 to .4315. So, even if I were to open the die my boolits would just drop through. What are your suggestions?

Thank you

[MikeS]

As for your die, it needs to be opened up as you stated, or you could just buy one the correct size, and put your current one away, never know when you might need it for a different gun. As to your mould, you have 3 choices, the first one (and most expensive) would be to send it out and have the driving bands opened up to the proper size, Erik at hollowpointmold.com can do this. Or you could take a few boolits cast from the mould, and attach screws to them to make them into laps, and try lapping out the mould to the size you need. Doing this will increase the size of the whole mould, not just the driving bands, which might be something you would want to do, or it might not. The easiest way to make your mould drop larger boolits would 'beagle' the mould. This is done by adding pieces of metal tape to the faces of the mould so it can't close all the way. While it sounds like it wouldn't increase the size of the boolit along the parting line, for some reason it does. The nice thing about 'beagling' the mould is it's reversible, so if you ever wanted the mould to drop the smaller boolits it does now, you could just remove the tape. Do a search on 'beagling a mold' and 'Leementing a mold', or 'lapping a mold', and you will get lots more info about it than my simplified explanation. If it was my mould, I would beagle it first, and see how that worked out, and leave more permanent solutions for a later date.

[heavyd]

I also forgot to mention how the bullets fit in the cylinder. .4315 boolits drop in and when they hit the band 3/4 of the way down they stop (I don't know what this is called). I have to push them through to get the bullet out. .4305's drop all the way through with ease. Not sure how this will affect what size boolits I can run. Would .4315's be okay if they can be pushed through?

[PacMan]

Assuming your are using a lbuesizer and not a Lee die i would open the die to .432 and then lube some up and shoot.The tight fit in the throats is good. If you have problems you could try beagling the mold and see what happens.

[oscar669]

Now I am confused. Why increase the diameter of the bullet if the cylinder throat is going to size the bullet to between 4.305 and 4.315 prior to the bullet getting to the barrel if the round would even chamber.

[felix]

There would be no point to it IF the cartridge is straight-on. Straight-on means the same friction/clearance alongside the case as it is chambered. The idea is to ASSURE complete closure of the chamber as the round is fired. ... felix

[Larry Gibson]

Now I am confused. Why increase the diameter of the bullet if the cylinder throat is going to size the bullet to between 4.305 and 4.315 prior to the bullet getting to the barrel if the round would even chamber.

There really is no reason to do so. I suggest you stick with the .430 sizer and push a different sized bullet through each throat. Ideally slight resistance should be felt. I also suggest you reslug the barrel with 3 seperate slugs and use a micrometer (seems you did?) to mic them. Sometimes using just one slug can give a false measurement for a variety of reasons.

BTW; How does the BH shoot with those .430 sized bullets?

Larry Gibson

[heavyd]

There really is no reason to do so. I suggest you stick with the .430 sizer and push a different sized bullet through each throat. Ideally slight resistance should be felt. I also suggest you reslug the barrel with 3 seperate slugs and use a micrometer (seems you did?) to mic them. Sometimes using just one slug can give a false measurement for a variety of reasons.

BTW; How does the BH shoot with those .430 sized bullets?

Larry Gibson

I will need to use a .431 die to get slight resistance in the cylinder. Slugged the barrel twice and both times the largest measurements were close to .432 with a micrometer. This was with wheel weight alloy so I can try again with all stick-ons so it will be even softer.

The .430's shoot well, maybe 1 inch at 50 yards. But, I have some old hard cast 200 grain RNFP which mike at .4315 and shoot 1/2 inch at 50 yards. I was getting these awesome groups with titegroup when I first started reloading 6 years ago. I would like to cast my own and hope to get this kind of accuracy or better.

[Iron Mike Golf]

1. Is your boolit size variance due to mold temp, alloy composition, or does it depend on which cavity the boolit came from (asuming a 2 or 4 cav mold)

2. If you can get consistent .4315 dia, then I'd go for a .432 sizer and shoot as cast, just using the sizer for lubing.

3. When you mike your boolits, are you measuring each drive band? Are they the same or close?

4. Yeah, use the stick-on. Maybe your weighweight composition is giving some springback and so a higher groove dia.

[heavyd]

1. Is your boolit size variance due to mold temp, alloy composition, or does it depend on which cavity the boolit came from (asuming a 2 or 4 cav mold)

2. If you can get consistent .4315 dia, then I'd go for a .432 sizer and shoot as cast, just using the sizer for lubing.

3. When you mike your boolits, are you measuring each drive band? Are they the same or close?

4. Yeah, use the stick-on. Maybe your weighweight composition is giving some springback and so a higher groove dia.

I will use the wheel weights to slug from now on. My Lee furnace is out of comission now so I will have a hard time getting ready for deer season.

I will order a thermometer so that I can get consistency. Right now I have been putting my Lee on 6 and that usually casts good boolits. The base of the bullets are usually a bit larger than the second band but I will hit it with the micrometer again. Thanks everyone for the help. When I get my furnace back from Lee I will start experimenting again.

[fredj338]

I don't find sized bullets really accurate for measure throats. Steel pin gages are a better bet. IMO, size to the throat dia. I agree, slug it & measure it again. Most are just not that large.

[heavyd]

I don't find sized bullets really accurate for measure throats. Steel pin gages are a better bet. IMO, size to the throat dia. I agree, slug it & measure it again. Most are just not that large.

I do not have steel pin gauges. Where might I find someone that would have them? A gunsmith?

[alfloyd]

"I do not have steel pin gauges. Where might I find someone that would have them? A gunsmith?"

Try a local machine shop, one that does turnning and milling operations.
They will be the best chance for having pin gauges.

Lafaun

[Char-Gar]

To about a 95% certainty, you mis-measured the groove diameter of you barrel. I am not saying that Ruger can't screw up and make one that large, but it is far, far more likely the measurement is wrong.

[mtgrs737]

I bought my own set of pin gauges, they are one of the best investments a cast boolit revolver shooter can make IMHO. Also IMHO if your bore measures .4315" then your throats need to measure at least .432" preferrably .433". You may get by with .4315" throats if your loading develops enough pressure to slug up the boolit to fill any gaps. I won't shoot any loads that don't drop into the cylinder completley and then fall out on their own when tipped up so as to allow room for the case to expand and release the boolit upon firing. Just my .02

[mtgrs737]

To about a 95% certainty, you mis-measured the groove diameter of you barrel. I am not saying that Ruger can't screw up and make one that large, but it is far, far more likely the measurement is wrong.

Using an alloy that is not dead soft can experiance "Spring Back" in the slug that would not give true size of the bore. I would use only pure lead to slug with.

[heavyd]

I have never heard of "spring back" but it makes sense. Without a doubt I will only slug with pure lead from now on. Hopefully it will slug out closer to .430 so I do not have to deal with all this mess. Should I size the boolits to the barell diameter or the larget cylinder diameter?

[ColColt]

This is what you need. I wanted a set but last time instead of chancing a back order, I called to see if they were available. They weren't at the time so, I'll be checking again. Good for measuring throats as well as a possible barrel restriction. OK, I just checked their website and it looks like they're back in again.

http://www.grizzly.com/products/G9794

[Larry Gibson]

I have never heard of "spring back" but it makes sense. Without a doubt I will only slug with pure lead from now on. Hopefully it will slug out closer to .430 so I do not have to deal with all this mess. Should I size the boolits to the barell diameter or the larget cylinder diameter?

Charger was little more straight forward than i was. Best to use dead soft pure lead to slug with. "Springback" is real with harder alloys. My suggestion still holds to slug each chamber seperately and the size the bullets to the largest throat. That's my opinion based on my experience, others are just as successfull with what they recommend but no sense having the cylinder throats size the bullets back down too much. With some bullet designs chambering issues arise if the bullet is larger than the throats.

Larry Gibson

[Char-Gar]

I am not straight forward..I am blunt! Some folks call that "harsh". . But often we get of on tangents because we accept without a critical analysis what somebody as posted.

If a guy has a .4315 groove diameter in his barrel, he has a problem that will not be solved by sizing a bullet. He needs a new barrel. Ruger will make a bum barrel every once in a while, but not that large.

Frequently we get folks here who don't know how to slug a barrel and/or measure the slug correctly.

To answer the poster, use a dead soft lead slug or fishing weight. Make certain the barrel is clean, clean, clean and then lubricate it with some oil. Force an over sized soft slug down the barrel and make certain it is not dropped or damaged when it exits the forcing cone. I stuff the frame window full of wadded paper towels to keep the slug from dropping on hard steel.

You then measure the slug while rotating it between the jaws of a micrometer. Do not use a set of calipers, no matter how costly. I have a $150.00 set of Starrett electronic calipers and they will not do the job near as good as a decent micrometer.

When done properly, the poster will find out his barrel groove diameter is about .430 to a max of .431. But that really doesn't matter, because the cylinder throats will most likely be larger. In fact, I would not bother with slugging the barrel.

Measure the cylinder throats with either a good pin gauge or an machinist expandable hole gauge that can again be measured with a micrometer. I have a set of Starrett hole gauges that I have used for years.

Again, don't try and measure the cylinder throats with a set of calipers. They are not worth a hoot for measuring the inside of a hole. I don't care what you read in some magazine.

When you have done all of this size the bullet to match the cylinder throats and go shooting.

I have read for years about "springback", but I have never been able to measure it, so I don't consider it a factor.