LBT WFN Design and Throat Seating

[ejcrist]

I've been interested in getting a LBT mold for 45 WFN 280 grain boolits for some time because I keep thinking about the fact that the boolit would be jammed well into the throat and get the best starting alignment than a lot of other designs. I double checked the RCBS-270-SAA's I have loaded and the front driving band is on the ramp leading up to the throat on a Ruger Bisley BH 45 Colt I have but it's not wholly in the throat. Has anyone had any experiences with the LBT boolits and found better accuracy than Keith SWC's? I know there's a lot of variables involved (velocity, twist rates, etc.) but I'm still dying to know how much a difference seating in the throat matters. I'd rather keep the number of boolit molds to a minimum since casting takes a lot of my time but if an LBT would do well I wouldn't hesitate to get a mold and turn out a good number of them. Any info would be appreciated.

Also, another point I thought about is if a LBT boolit is sized to the throat diameter and sitting in the throat, after firing wouldn't that make loading subsequent cartridges difficult if not impossible to chamber fully since there's be some fouling in the throat where the previous boolit exited?

Thanks, Gene

[crabo]

Here's some 44s for you. The SWC is the RCBS 250K, the plain base LBT is a 260 grain, and the gas check is a 280 grain.

All of them will shoot 2" or less at 50 yards, off the bench with optics.

[RobS]

You can design a mold to have the front drive band sit into the cylinder throat which can help keep the round more inline with your barrel (assuming the gun is made correctly). There are many WFN style designs that are and can be produced by many of the talented mold makers. Dan at Mountain Molds can cut you nearly anything you would like and so can Tom at Accurate molds. Mountain Molds has an online program that you can actually sit down and start designing your own specifics where as Accurate Molds you simply contact Tom via email and tell him what you are after and he will draw up and then catalog the design. Tom is very good with communication and usually has things up online in the catalog in less than 24 hours.
http://www.accuratemolds.com/
http://www.mountainmolds.com/

If you know how much front drive band you need to reach the cylinder throat then you have a pretty good idea what you are after. Next is how long of a nose you prefer/need, the meplat diameter, etc. You can look at Accurate Molds catalog and the likelihood that someone has already designed something you are after is very good.

[crabo]

Have you measured your cylinder throats with pin gauges? That is the place I would start.

[ejcrist]

Have you measured your cylinder throats with pin gauges? That is the place I would start.

Yep - that's the first thing I always check and consider it the most important. The 280 gr GC LBT you showed above looks like it would fit in my Ruger's throat nicely. I'd bet that boolit would shoot very well.

Rob - I have two of the Accurate molds and really love them. I was thinking to go that route as well. I've never ordered a Mountain mold but have been to the website. I think in the end I'll probably end up with custom molds for each revolver. T think going forward, if one of the molds I have doesn't fit the chambers exactly right (drive band in the throat) I'm going to order the correct dimensioned boolit mold from Accurate or Mountain first before working on the load. This is an interesting subject and one I think about quite a bit.

Gene

[crabo]

Gene, do you want a GC or plain based boolit?

What distances are you planning on shooting at?

How fast?

[ejcrist]

Gene, do you want a GC or plain based boolit?

What distances are you planning on shooting at?

How fast?

I've been shooting RCBS's 45-270-SAA which is a plain base Keith type SWC and drops from the mold at about 280 grains cast from straight WW's. For umpteen years I only pushed it around 850 fps from a Ruger Bisley BH with 8 grains of Unique, and that was fine for steel silhouettes out to 100m and varmints. But this past October I took her pig hunting in TX and all that combination did was drill holes straight through with no expansion and it took a full cylinder to put 'em down at about 30 yards. After that experience I knew I needed to push the boolit at least 1,000 fps and preferably 1,100-1,200 for good expansion. Also I want accuracy of no less than 6" at 100 yards for both steel silhouette which I use for practice and pig, deer, and javelina hunting. Also to note, I don't have any scopes mounted - all revolvers I own are open sights which I prefer.

So to summarize:
- Accuracy of 6" out to 100 yards w/open sights
-PB 280 gr WW boolit
-Velocity of 1,100-1,200 fps

Gene

[Piedmont]

Gene, Your bullets are not going to expand at 1100-1200 fps. unless they are HPs and soft enough. They will blow larger holes with the extra velocity, though.

[ejcrist]

Gene, Your bullets are not going to expand at 1100-1200 fps. unless they are HPs and soft enough. They will blow larger holes with the extra velocity, though.

Bigger holes is the goal so I'll be happy if that's the end result regardless of what gets me there. You don't think they'd expand a little more when they impact the pig though? I agree the extra speed will create a bigger wound channel by itself due to shock but I'd think a wheel weight cast boolit would flatten/deform a little at that speed too. I don't know, maybe I'm wrong.

Crabo - I just measured the front driving band length of an as-cast 45-270-SAA and found it was .095". The Accurate mold 45-270K is also .095" so if I crimped in the groove just below the Accurate boolit should extend the same distance into the throat. I also compared the boolits I normally shoot in the 44 (429421 w/band length of .095") to 43-250K (also .095") and 32-098-SWC (.07") to 31-105K (.095"). So it looks like the only currently made Accurate mold that's similar to the molds I have would extend the same distance into the Ruger throats I'm loading them for, with the exception of the 32 boolit. So I'd have to submit a new design if I go that route for something that extends into the throat fully.

Not to make things any more confusing, but I re-read the last paragraph under the "Bullet Design" tab on the Accurate website http://www.accuratemolds.com/bulletDesign.php
...and there's an illustration of why it's better to have a shoulder built into a given mold so the boolit isn't too wide when it enters the throat. I know this describes a different situation, but one thing I'm taking away from it is that the front driving band should probably not be above the ramp leading into the throat because even if the boolit were sized exactly the same diameter as the throat it wouldn't fit because you can't fit a .430 boolit into a .430 throat - it would have to be just slightly smaller. Also, I've read many a times that a cast boolit shoots best when it's sized to the throat or .001" larger, but of course if that were the case you wouldn't be able to chamber them at all if the front band extended into the throat above the ramp leading to the throat.

I'm beginning to think I'm trying to solve a problem that doesn't exist and should maybe just be happy with boolits up to the throat but not actually "in" the throats.

Gene

[crabo]

I wouldn't have confidence in my groups at 100 yards with iron sights. I need some kind of optic to help me out. I shoot open sights to 100 yards and beyond, but not when testing ammo. Maybe I just haven't come up with a good target for long range with iron sights.

[ejcrist]

I wouldn't have confidence in my groups at 100 yards with iron sights. I need some kind of optic to help me out. I shoot open sights to 100 yards and beyond, but not when testing ammo. Maybe I just haven't come up with a good target for long range with iron sights.

Copy that. I don't do much testing if any at 100 yards but I'll shoot a couple of groups to see where they're impacting and what kind of groups can be expected. Also, if I can reasonably expect to hit rams if I do my part during the monthly match. All my accuracy testing is done at 25 and 50 yards.

Gene

[crabo]

There are a lot of loads that fall apart between 50 and 100 yards. That is why I test at both.

[ejcrist]

You got that right! With some loads I can pretty consistently hit the steel chickens and pigs but then it's a crapshoot on the turkeys and rams. I have a couple of theories. For loads that chrono around 1,200 I believe the bullet transitions to subsonic beyond about 50-60 and then it's unstable. The second is that boolits long relative to the twist start slowing down after 50 and destabilize. Or maybe it's a combination of both. I noticed what you're saying when I took up handgun silhouette. That game has taught me more about handgun performance than anything else. The biggest thing I learned is that I don't know a whole lot. The main reason I shoot it is for hunting practice at hunting ranges. It's not exactly the same as hunting where the ranges vary and the target could be moving but I found it's the closest thing that works best for me.

[Screwbolts]

A call to Verel Smith is the place to start, he will get all the info he needs from you to cut your mold for a perfect fit. All the guessing and pondering is useless, Call Verel and tell him what you want ant he will fit it. It is that simple!

Ken

[JSH]

I think the super sonic to subsonic thoughts have merit. We have had some pretty long discussions on this after a lot of matches. It needs to stay super sonic most of the way to the furthest target. Or start it at sub sonic and keep enough momentum all the way to take the BB rams down.
A light projectile screaming out of a wheel gun is not the answer. That was tried for several years and was the major cause of the down fall of the 357 max, IMHO.
Don't ask me why, but if I can scratch a 20+ with a revolver gives me way more happiness than shooting a 40 with a single shot.
IHMSA is a fine sport and a good learning tool as you mention. I just wish more folks would give it a try. I think a lot of them don't play the game because the find it tougher than they thought. Same goes for bullseye.
Jeff

[ejcrist]

I think the super sonic to subsonic thoughts have merit. We have had some pretty long discussions on this after a lot of matches. It needs to stay super sonic most of the way to the furthest target. Or start it at sub sonic and keep enough momentum all the way to take the BB rams down.
A light projectile screaming out of a wheel gun is not the answer. That was tried for several years and was the major cause of the down fall of the 357 max, IMHO.
Don't ask me why, but if I can scratch a 20+ with a revolver gives me way more happiness than shooting a 40 with a single shot.
IHMSA is a fine sport and a good learning tool as you mention. I just wish more folks would give it a try. I think a lot of them don't play the game because the find it tougher than they thought. Same goes for bullseye.
Jeff

Totally agree with everything you said, especially about shooting IHMSA or NRA silhouette. I think the best score I ever shot with a wheel gun was 21 or thereabouts. I'm happy with anything over 0 some days when it's cold a windy. I've invited umpteen people to the matches but never get any takers. I think the next time I bring it up I won't mention the ranges the targets are shot at and just say the word "steel" since that seems to be best flavor as of late. Without a doubt though, handgun silhouette has been by far the best training I ever had when it comes to handgun hunting.

[JSH]

I ran with a SW 29 105/8" for a while. Best I ever scratched out with it was in the mid twenties. All kinds of loads and bullets.
My casting/shooting buddy bought an FA. Used 2400 and a 429421. I shot it first in the very first match. Ran one off of getting into Int. class. Put me all the way intoAAA.
Been playing with the 357 max and am pretty happy with it. Got a 41 mag and a 45 colt to tinker with this summer.
Picked up one of the brass NOE 45-270-SAA molds. Got some HP and FN cast up.
Your original thoughts on sizing for the throat. As long as the are all the same have veral fit it to your gun. I do have to admit I am satisfied with less from a production line gun than a semi or full custom. I have not had much luck with trying to get many "stock" type guns to shoot cb's as well as I would like, but it can be done. Just not as easy or as cheap as an excellent made gun.

[RJM52]

"I'm beginning to think I'm trying to solve a problem that doesn't exist and should maybe just be happy with boolits up to the throat but not actually "in" the throats."

Good shooters have been hitting small targets with stock revolvers for many many years without overthinking things.

One of the problems I have with boolits that are too close to throat size is not being able to or having to really push to seat them into the chambers. This is especially true with a FA 654 .41 Magnum I shoot a lot. In shooting this gun out to 800 yards I have not seen any difference in LBT, Keith or for that matter just a plain RN design.

As to boolits expanding...if you want that to happen get a good HP...otherwise if bone isn't struck it's going out the other side... I recovered an Accurate 41-215V after passing through 4 water jugs and into a bullet proof vest insert..and except for the rifling marks it look as it did when loaded.

Bob