When is it not a Wadcutter?

[Brian Albin]

Hello long range shooters,
I am wondering how much nose a revolver bullet requires to have long range flight stability and not be short range only as I read of the Wadcutter. I am going to have a mold made and want as long a bearing surface as I can have so the cylinder can hold the bullet centered as it travels through the barrel throat and not turn loose of it until the barrel has a good grip on it. This makes me want as short a nose as possible to avoid excess weight. I am going to have the mold hollow pointed, but even so, I would like to know how short a nose I can get away with and have a bullet with target accuracy for long range practice; say out to 200 yds. Or at least 150.
My ctg is the stubby little 45 Auto Rim.
Attached here is a drawing from the Mountain Molds simulator of a bullet which will weigh 270 grs solid before being sent off for hololow pointing to reduce weight. I am worried that the nose may be too stubby. But to lengthen it while preserving this length of bearing surface would add 20 grs.

[Brian Albin]

Here are two versions of the 290 gr bullet, one with meplat diameter equals 60% of bullet diameter. The other has a 55% meplat. The 270 gr bullet has a 60% meplat.
What do you think? Is the nose of the 270 gr bullet acceptable? Or ought I to go with the 290 gr?


Brian

[17nut]

The nose doesnt give stability just better BC.
A flat nosed bullet has a terrible BC and loses speed fast, the slower it goes the longer wind can push it around.

What is long range for you and do you intend to shoot from a revolver?

As an example:
Lee .452-255-RF has a BC of .21
Launch that at 950fps from a 7½" barrel (QL guestimates says it's max speed for the small amount of powder space avaliable in a 45 AR).

If you sight it on at 100yards it will be @5" high at 60yards and 44" low at 200 yards (830fps).

Is that long range?

300 yards 139"~11½feet low (768fps)
400 yards 293"~24½feet low (715fps)

See it doesnt shed speed fast it just never started going fast in the first place, and you'll never get that in that small case at no more than 17400psi.

[runfiverun]

I think you might want to re-think that front drive band.
the AR chamber is the acp chamber you don't have that much free bore to work with.

[Brian Albin]

Thank you for the advice, runfiverun (http://castboolits.gunloads.com/member.php?4217-runfiverun). I have not yet bought my cerrosafe. I do intend to make a cylinder cast before ordering the mould.

Brian

[too many things]

OK I know I didn't read this right
200yds with a 45 auto rim? did I miss something ? I could have
just asking before the cubs win and you will need all the ammo to stay alive

[runfiverun]

not a big deal but you can always just change that front drive bands angle to match your throat.
I'm assuming this is in a revolver.
and I'm just remembering my attempts to headspace on the edge of the RNFP boolit in my 624 using acp cases.
things got tight pretty quickly and loading the cylinder turned into a pain.

[reed1911]

I run a 300g SWC in my AR from time to time, and the 280g SWC fairly often. They both do well at 100yds, but that is all my poor eyes will take and I have to make sure I don't drink coffee when I do. Bearing surface is .535" and .518" respectively.

[Geezer in NH]

A wad cutter is not a wad cutter when it does not cut a full diameter "wad" or hole in a paper target.

That is all it's original design was created for, to make scoring easier.

[Brian Albin]

Thank you, Ron Reed, for telling me the length of the bearing surface of your bullets. Mine as drawn thus far with an eighth inch wide front band, would be half inch.

Brian

[reed1911]

Brian,
Those numbers include the band since it too is full diameter.

[paul h]

For bullet stability you need to first look at the overall length of the bullet, the twist rate of your barrel and your muzzle velocity. The nose length doesn't contribute to long range stability in and of itself and if the bullet is too long for your barrel twist and muzzle velocity it will hinder stability at all ranges. But, it does affect the bullets bc and hence ability to retain velocity which does affect long range accuracy.

The advantages of a full wadcutter are two fold. The long bearing length helps align the bullet when exiting the cylinder throat and entering the forcing cone in the barrel, and it also takes up significant powder capacity in the case which allows the consistent burning of small charges of powder which aids accuracy.

Personally for longer range target work I would choose a lighter bullet 230-250 gr and work on balancing bearing length with powder capacity as IMHO you want higher velocity (relatively speaking), not lower velocity in such a small low pressure case.

The most accurate bullet I've shot and cast from a revolver was a bullet that was on the lighter end of weight for the caliber (310 gr .476"), had a bearing length of approximately one caliber and had an LFN nose that was ~80% of the caliber in length when measured from the front of the crimp groove to the meplat and lauched at 1000 fps. I don't know that this was a magic combination, but it shot moa groups at 100 yds. I'm pretty sure my 400 gr bullets clocking 1200 fps would shoot the same but I only tested them at 50 yds where they grouped 2 moa.

[DougGuy]

You have a short .45 case, which means that you won't have enough room for a long boolit and still hope to put some powder under the boolit. Also, you won't find an RF style boolit with any size meplat that will be stable and accurate past about 100 yards. They simply do not exist in this caliber or people would be taking deer at 175 yards with a Super Blackhawk.

The truth is, it doesn't seem to matter how long the cylinder throats are, so long as they are sized correctly and all even. This is why the 45 ACP cylinders in Ruger revolvers shoot quite well.

For a boolit to still be in the throat, and engage the forcing cone, you would need almost a full wadcutter, since any ojive will permit the boolit to come further out of the cylinder throat before it contacts the forcing cone. I would think that the LBT style WFN boolits would have the best chance of still being in the throat, and the cylinder at the same time which really would be your best shot, and these are short enough that they could be loaded in the AR case. You won't be able to load much longer of a boolit in the AR case without running into some extreme pressure on ignition.

L to R: LBT 250gr OWC Ogival Wad Cutter, LBT 250gr WFN-PB, LBT 250gr WFN-GC

http://i1202.photobucket.com/albums/bb374/DougGuy/Reloading/250_LBT_TRIO_zpshh2co3gc.jpg (http://s1202.photobucket.com/user/DougGuy/media/Reloading/250_LBT_TRIO_zpshh2co3gc.jpg.html)

[paul h]

The WFN's have a reputation of starting to fly wild at somewhere around 150-200 yards so are likely not the best choice for long range work. I would suggest a meplat that doesn't exceed 70% for long range work. I sent some of my 460 gr .476" wfn's to a guy down south for some testing and while they would group into an inch at 50 yds when driven 1100 fps, he said at 200 yds he wasn't able to hit his target while his 400 gr lfn's were grouping right in there.

I don't know if it was the WFN shape, or the additional length of the bullet that caused the inaccuracy at extended range, but others have said the WFN's tend to fly wild at some point.

[Brian Albin]

I thank you fellas for the additional information.
　
Brian