LBT mold problem

[gunslinger20]

Ruger BH Bis 45 colt cylinders reamed to .4535 LBT 280gr. wfn g/c sized .4540.
Boolits wont chamber cuz the front driveing band hits the throat. I can size alittle smaller but then I get a boolit that is too loose in the cylinder throat. Boolits actually weigh 310 gr. I had to trim the brass way under size to get enough clearance to chamber. Have you guys run into this problem and how did it turn out?
Thanks gunslinger20

[knifemaker]

what is the Dia. of your barrel grooves? If it is .452 or under you can size the boolit to .453 or .4535 to fit your throats and give a good sealing fit in the barrel.

[gunslinger20]

.443 across lands .451 across groves in the boolits so it would be reversed in the barrel. The same on both ends of the barrel. I realise this setup should seal but I am a fanatic when it comes to accuracy and I am trying to hold the valosity up. With the loose boolits in the throat I can barely get 1200 fps with 23.3 grains of 296. I have not shot the shortened cases with the .4535 yet.

[greywuuf]

I have exactly that problem with my 300 grain LBT WFN design. be very careful sizing it more as mine tend to get un uneven driving band from that, being obviously sized farther forward on one side than the other ( probably poor production on my part as well as a poorly fitted punch)

I ordered a MiHec 330 with longer thinner nose, hope it works out better for me.

[cbrick]

The title of this thread is a bit mis-leading, it's not a mold problem it's a sizing die problem.

I highly recommend using a nose first die such as the Star or the LEE sizing die. Nose first with a flat punch against the flat bullet base will size the bullet more concentrically. If you get an inexpensive LEE die you can ream/hone out the die very little at time until you get a mild snug fit in the throats. From an accuracy point you want the front driving band fully inside the throat when the round is chambered. From a sealing and alignment point you want the front driving band a mild snug fit.

That's how I load for my long range revolver match loads. Shortening up the brass may work but I don't think you'll acheive the accuracy your looking for that way and you'll reduce the powder capacity. The whole idea is to make the bullet fit the throat, not shorten the brass so that a bullet that doesn't fit sits in front of the throat.

Hope this helps.

Rick

[Dale53]

You cannot put a quart of liquid in a one pint jar.

You cannot easily seat a cartridge that is larger than the hole - it's just as simple as that.

The bullets, as sized, need to be no larger than a "slip fit" in the chamber throats for "best case".

In fact, .001" less won't hurt a thing. Believe me, it won't.

You're trying too hard. Just relax, size to slightly below the chamber throat size, load and fire. You will get EXCELLENT results as long as your alloy is correct and using a good lube.

Dale53

[Piedmont]

Gunslinger, That is a problem you run into with a long front band outside the case. You can nose first just everything in front of the crimp groove to .452 and knock it back out, or size the whole bullet smaller than you might like (say .452"). It is a problem with the design, or at least a shortcoming that must always be considered. If that front band were shorter, yet still .454 it would fit in the leade portion of the cylinder (the funnel just in front of the case and just before the cylinder throat proper) without problem.

One thing I did on a Mountain Mold I designed was make the front band .08" with a bore rider in front of it. This allowed using a properly sized bullet and allowed easy chambering. Dan at Moutain molds has written about revolver designs and addressed this problem in one of the articles on his website.

I wouldn't trim my cases as a fix because you will promote gas cutting.

[PacMan]

Just curious what was the throat size before you reamed to .4535?
Also what cbrick said about being a sizing problem not a mold problem. Cbrick and Dale hit it on the nose with a slight variation of fit. Both ways work.
I have also done what piedmont sugest about sizing the nose slightly but i have a Saeco sizer and i adjust the return pin so that i can size nose first. (do not use that method any longer) I have been sizing to a snug slip fit and have no problems with chambering.
If you have good case tension on the bullet i would think that any velocity diffrence are small at best.

[gunslinger20]

I have two lee push through sizers that I have honed out, one is the over cylinder size .454 that wont chamber and is the boolit that I want to shoot. The .453 is the one that is too loose for my likeing, but will chamber cuz its under size. The throats were .451 before reaming. The cases trhat I shortened still have space between the powder and the boolit base. I also already tryed just sizeing half of the boolit and knocking it out the bottom and it does work but what a pain. With that process I have to size in the oversize die to put on G/C then size half of the boolit for the over size driving band then knock it back out.

[cbrick]

The .453 is the one that is too loose for my likeing, but will chamber cuz its under size.

So what is the probelm? Hone out the .453" die about a half thousands.

Not many people get as anal as I do about sizing & fit for my long range match revolver but even I think that worring over .0005" is picking the fly poop out of the pepper barrel. I do understand the challenge of making it as perfect as possible, assuming you hone out the .453" die let us know the results of accuracy & velocity testing compared with shooting it before enlarging the die. Curious minds want to know.

Rick

[RobS]

All the molds I designed for the revolvers have drivebands that extend into the cylinder throats and with such a person has to size to or under the cylinder throat diameters. Differences in lead hardness also comes into play in sizing die selection due to "spring back". A softer alloyed boolit won't spring back as much as a harder one so if you happened to not have issues once and now you do that is a possibility. The time frame in which a person sizes their boolits also can have an effect as well. +1 on this:

From an accuracy point you want the front driving band fully inside the throat when the round is chambered. From a sealing and alignment point you want the front driving band a mild snug fit.

[gunslinger20]

So what is the probelm? Hone out the .453" die about a half thousands.

Not many people get as anal as I do about sizing & fit for my long range match revolver but even I think that worring over .0005" is picking the fly poop out of the pepper barrel. I do understand the challenge of making it as perfect as possible, assuming you hone out the .453" die let us know the results of accuracy & velocity testing compared with shooting it before enlarging the die. Curious minds want to know.

Rick

Its very tough to only remove .0005 then I end up with two .454 that wont chamber. The .4535 will chamber but is .0005 under the throat size of the cylinder. I thought about polishing the leed of the throats to try to get a little more clearance for the driving band but I dont know how critical it would be to get all leeds exactly the same, which would be almost impossible to do.

[gunslinger20]

All the molds I designed for the revolvers have drivebands that extend into the cylinder throats and with such a person has to size to or under the cylinder throat diameters. Differences in lead hardness also comes into play in sizing die selection due to "spring back". A softer alloyed boolit won't spring back as much as a harder one so if you happened to not have issues once and now you do that is a possibility. The time frame in which a person sizes their boolits also can have an effect as well. +1 on this:

So If I use a little softer alloy when I have to use a little force to seat the cartrige in the cylinder are you saying it will swedge the boolit enough to not cause excessive pressure spike and still have the fit in the cylinder that I am looking for? This is a new mold so I have had this issue all along with it.

[cbrick]

Its very tough to only remove .0005 then I end up with two .454 that wont chamber.

Not really, kind of easy actually if you go slow and check often. Get the very finest lapping compound you can get, take a short brass rod and cut a slit in the end. Place a piece cloth in the slit and the other end of the rod in a drill motor. Dampen the lapping compound and place it on the cloth. Turn the drill motor slowly while running the cloth in and out, don't hold it in place, keep it moving in & out. If you go slow you'll only be removing a tenth or two at time, check often. Clean the die of lapping compound, lube an un-sized bullet and size it, check in the throats for proper fit. If more is needed do it again until your happy with the fit. At most you will only be polishing the die and removing very little metal.

Worst case is that you ruin a $12.00 die and need to get another. Go slow and gunslinger20 should be a happy camper.

Did I mention going slow and checking often?

Rick

[cbrick]

This is a new mold so I have had this issue all along with it.

gunslinger20, from everything you have posted in this thread it sounds very much like the mold is spot on. This is a sizing the bullet issue that your not happy with.

It is not physically possible to cut a mold that will drop bullets to an exact diameter. Why? Because if you change the alloy only very slightly it will change the as cast diameter of the bullet that falls out of it. If you change the mold and/or alloy temp while casting you can change the diameter of the bullet. The only issue with the mold is that it drops a bullet large enough for your application so you can size it down to your needs.

Rick

[gunslinger20]

Let me clearify There is nothing wrong with the mold, I love the design thats why I am so intent on getting it to work for me. Yes there is a fitment problem for my application. Had I ordered the crimp a little closer to the boolit nose all would be well.

[PacMan]

I would load and shoot the .453 bullets before i done anything at all. What alloy you using? If they are WW you could try water droping them and let them sit over night and then run thru your 453 die and they will most likely spring back to .4535 or so. Try them WD and see how it shoots. If you want aircooled hardness after you size the WD bullets put them in a oven at 350 deg for one hour and then remove , spread out and let cool at room tempeature and you now have AC without the wait.
Just some thoughts that may help you decide if you really need that other .0005 or not because once you open the die if you change alloy or time between sizing you may be back to square one.
Perfect fit can be a juggling afair at times.

[gunslinger20]

I am useing acww and wdww. Its supposed to rain for the next 3 to 4 days so im probably down for a time as far as shooting.

[PacMan]

Gunslinger if you are able to cast while it is ranning try what i talked about earlier. Cast up about 15-20 bullets and water drop them. As soon as you cast them while they are still fairly soft run a couple thru your .454 sizer and see what you get. Set some aside to harden for a couple of days and then run them thru your .453 sizer and see what you get again.
Also take the ones you run thru the .454 sizer and run them thru the .453. Most likely you will have three diffrent size bullets(the diffrences will be small) one of which may be what you are looking for.If so try shoothing them and see how it goes.
If you get the size you want and prefer to shoot some AC use the anneling process i described after they are sized and you are on go.
Now follow cbrick advice on enlarging your die if needed but remember that if you open it up to get your prfered fit you will only get the same results with the same hardness of bullet.If it sizes at .4535 with a water droped bullet it may only size to .453 with AC bullets.

[RobS]

So If I use a little softer alloy when I have to use a little force to seat the cartrige in the cylinder are you saying it will swedge the boolit enough to not cause excessive pressure spike and still have the fit in the cylinder that I am looking for? This is a new mold so I have had this issue all along with it.

I can't say if a softer boolit will chamber or not but it would swag easier than a harder one. The .0005” over will not be that significant to create any concerns with over pressures. What I was saying was an alloy of different metallurgy (softer) may very well drop smaller from the mold and a different alloy could also size differently depending on it's BHN at the time of sizing. A harder boolit will springback where as a softer one not as much. Pure lead doesn't springback to an effect notable in normal measurement and is the reason people use pure lead to slug their barrels.