Front driving band size.

[Lost Dog]

Now I shoot almost exclusively cast SWC'S in my pistols. And every one of them, regardless of design and year, have smaller driving bands. And I never paid that one single thought either as they all shot just fine.

A couple years ago I read an article by a fella on a site that appears to be well thought of as he's a kinda honcho or something on that site. And far be it for me to say anything about another caster, loader, and shooter. Wasn't raised to speak poorly about another. But, this fella was saying that an undersized driving band is a bad thing and the bullet hasn't got a chance in being remotely accurate. He went on to say that he had most of his moulds opened up to have oversized front driving bands, and on a few, he said even that didn't help. His story was that a smaller front driving band was an invitation to bullet hopping and skidding up and down the bore and never will they shoot right. And naturally he sang high praises for the Keith style SWC, and usually cursed most others. From what I read from this guy, he was cussing one mould that was not to his liking and later was lumping in many more and sighting the front driving bands as the deciding factor for all.

So, all you well versed and studious members (and I mean this not in a facetious way either) what do you think? Do front driving bands all need to be bore size or bigger? Or can they be slightly smaller like on the majority of moulds made yesterday and today? Tell me what you think.

 

[RicinYakima]

There are two common ways to align the bullet in the cylinder: one is to have the driving band a push fit into the throat, the other is to control case sizing so that the case aligns the bullet. The second depends upon luck of sizing die, or not sizing full length. When I was shooting NRA Bullseye two generations ago, we only sized the case to the base of the WC, so the rest of the case would align. Now it appears that high accuracy revolver shooters tend to load big bullets in unsized cases and use a "profile type crimp" die to just reduce case diameter enough to chamber. FWIW, Ric

 

[fiver]

well that front drive band is probably gonna be re-sized a time or two on it's way to the barrel anyway.
the way I look at it is how much fitment am I gonna get?
a 356 front drive band in a 38 special case in my 357 revolver is gonna travel a ways before it hits the throats.
as it goes through there it's gonna hit the barrels throat and this is where things start to matter.
now we gotta work on shape and diameter.
is that band gonna take that cylinder right there at full value or is it gonna start being squeezed a tick as it is engraved by the rifling pushing the excess lead out to fill the groove depth.

now in a 357 case is that slightly undersized front band big enough to hold the case square to the cylinder bore [in the throats] as the rear drive band follows it or is it gonna be tilted [sliding up the ramp] towards the opening.
be dang hard to chamber if it was full diameter.

now what about the nose?
did he touch on the nose at all?
that's the first thing to get to the barrel and if it's a bore riding type/diameter it should be guiding that drive band into place to take the rifling square on.


I don't use a ton of the swc type bullets and prefer the rnfp style myself.
I know they are laying on the bottom of the chamber and are riding along there for a bit probably even hitting the barrels throat a little bit of an angle.
but the rounded nose is for sure aligning itself in that tapered cone of a throat pulling the base along with it as it comes through the cylinders throat.

 

[Rick]

Now it appears that high accuracy revolver shooters tend to load big bullets in unsized cases and use a "profile type crimp" die to just reduce case diameter enough to chamber. FWIW, Ric

Or . . . What I do for 200 meter revolver accuracy is use a heavy for caliber bullet sized to a mild snug fit in the throats. Brass sized only to the depth the bullets seats. When a cartridge is chambered the front driving band is inside the throats, bullet isn't sized down or shaved from the edge of the throat and it's centerline is aligned with the centerline of the bore. By the time the leading edge of the front band reaches the forcing cone the center and rear driving bands are still in the throat keeping the bullet aligned with the centerline of the bore. When the rear of the bullet is clearing the throat the front band is engraved in the rifling. Bullet stays as straight as possible and pressure is fairly well contained behind the bullet until the entire bullet is in the barrel.

I did crimp testing a few years back and with these loads the type of crimp made little difference. The main concern is just enough crimp to keep the bullets from pulling under recoil. Any more crimp than that serves only to be tough on the brass.

.

 

[Lost Dog]

Well then. From what has been presented thus far a slightly smaller front driving band is not detrimental to accuracy and performance. That has been my opinion all along based purely upon years of shooting SWC'S in my wheelguns. And again, my reason for bringing this up was based upon the remarks of a presumed well versed and seasoned shooter and caster. The manner in which the "undersized" front driving band being so horrible to cause him to alter moulds frankly was worrying me. I'm not a competitive shooter. Nor study constantly as others do. Just an older guy retired to the woods with his own range that likes to load 'n shoot. However, I am quite patient and willing to investigate and learn from what I find, and especially from knowledgeable individuals that populates this forum. My thanks for the detailed and informative responses.

 

[Brad]

It MAY not matter at 25 or even 50 yards but to someone like Rick who was shooting at 200 it certainly could.
A wise man on another forum always liked to say that it only matters when it does.

I would prefer a full diameter front band every time if for no reason other than peace of mind. I KNOW it will never be detrimental to accuracy and that gives me more confidence in my ammo.

 

[Ian]

I'm with Fiver, though there is no "absolute right way" to fit a revolver bullet that will be the best solution for every gun or situation. If I want accuracy in a revolver I go for RNFP bullets cast hard (WDWW). And just the right amount of slop in the action so the cylinder can float just a titch. That doesn't mean the SWCs can't shoot, oh boy can they, but when I use them I tend to have better luck with long front bands that are large enough to be sized along with the rest of the bullet at about half a thousandth smaller than the cylinder throats (I ream all mine so this is easy to do). Even with half a thousandth clearance they take a shove to get in there after a little bit of fouling starts to accumulate.

What I don't like about 'undersized' front bands or undersized noses is that if you're sizing the main driving bands down to, say .358" exactly to fit .3585" throats, and your nose band is .355 or .350 like some of the SWC designs are, and further you're a cretin like me who uses a base-first lube-sizer, the bands usually won't be concentric with each other and that WILL matter when the bullet makes it into the forcing cone. The targets will for sure tell us what the revolver likes, and they might not all speak the same language. You just have to find out.

 

[Ian]

A wise man on another forum always liked to say that it only matters when it does.

Bass and Bret pretty much said all anyone needs to know about handloading cast bullets: "It only matters if it does", and "Fit is King".

 

[Brad]

Bass was very wise. I really miss him and his knowledge

 

[RBHarter]

I can't really speak to this with definitive evidence. But here goes . When I size for an HP9 to 358 on a particular 358-125 RNFP it effectively creates a full band in front of the crimp groove it shoots better than the as cast will plunk in the P98 .

The RBH a takes everything as cast with 4537 throats ,typically as cast for 3 moulds at 454. The 1917 S&W shoots very well but as noted all of the moulds are big and need to be sized 452 so the long seated ACP is in the throat .
I have a 430426 opened to cast 448 on the bottom 2 bands . With a paper patch the front band is 440 while the lower bands are 454 dry wrapped. In the 92' this makes zero group difference load for load with as cast 454424 or 452-255 RNFP.

 

[KHornet]

Opinions, can be accepted, rejected, ignored etc. However regarding this thread, I tend to accept what Rick says.

 

[Rick]

As was mentioned there is a difference in what you are loading for. In post #4 is how I load my revolver match ammo, if the ammo is for a defense and or a carry gun I would size bullets slightly smaller and they would pass the plunk test. In the long range match rounds while they of course all chamber things are a bit more snug. There is quite a difference in 200 meter revolver accuracy and minute of chest cavity at 5 feet.

.

 

[Lost Dog]

Logically if an elongated projectile is in static, and motionless status, remotely centered in the chamber of a property aligned cylinder then that's a good start. When the projectile is forced into the throat of the chamber by powder ignition, the concentrated thrust behind it forces it towards the forcing cone and barrel entrance. When the projectile is clearing the cylinder's end, it has already well entered enough into the forcing cone and leading end of the barrel with as much alignment possible provided by chamber and throat. Once free of the chamber, the projectile is well on its way down the bore toward its intended target.

I trust the above is somewhat common towards both round nose and semiwadcutter being that they're both elongated projectiles performing the same function. And thus taking into account the mechanical actions of the projectile exiting the chamber and simultaneously entering the forcing cone and such that a slightly smaller front driving band would be of little consequence with the body of the projectile actually being guided and such. Whereas the round nose and RNFP styles usually have little or no front driving bands at all yet they function well. And by that logic, the SWC with full or reduced sized front driving band will travel equally well as the rounded projects.

The above is what I understand and such from the replies and input here. In essence, the main body of the bullet, with a sound and solid base, are the guidance for a revolver bullet and the nose design is of little importance. And as such a reduced sized front driving band hurts nothing. Is that about it?

 

[Rick]

No not exactly Dog, re-read post #4 for long range accuracy. By having the front band a mild snug fit in the throats when the round is chambered goes a long way to aligning the center line of the bullet with the center line of the bore and keeping it that way right out the muzzle. The smaller the front band in relation to throat size the poorer the alignment. As an X cop your probably programed to think short range defense shooting where such a bullet fit would make far less of a difference. My shooting history is much the opposite with long range revolver accuracy being the vast majority of my shooting. The closer/better the fit as I described does make a big difference.

.

 

[Lost Dog]

...When a cartridge is chambered the front driving band is inside the throats, bullet isn't sized down or shaved from the edge of the throat and it's centerline is aligned with the centerline of the bore. By the time the leading edge of the front band reaches the forcing cone the center and rear driving bands are still in the throat keeping the bullet aligned with the centerline of the bore. When the rear of the bullet is clearing the throat the front band is engraved in the rifling. Bullet stays as straight as possible and pressure is fairly well contained behind the bullet until the entire bullet is in the barrel.
.

Not trying to sound stupid on my part, but I did read your post and the above statement stood out describing the projectile's travel and alignment from it. And I'm not being rude or disrespectful here as well. I'm just a little confused now. Ya lost me...
And then why in the world do most all SWC'S have smaller front driving bands then? I guess I'm missing something else here too. Ok. I'll hush up and leave it alone. Nevermind. Thanks guys.

 

[RBHarter]

I should add that in everything longer than ACP family takes advantage of fire forming and neck sizing , going so far as to use the 303 head tape means of better centering the case in the 92' for first fire. It is possible that the other tricks and single sizing for hunting consistency loading negate anything that might be seen in my shooting.

It is my perception that that every step taken to remove clearances, minimize tolerance, smooth transitions and straighten the parallel tube lines and square the perpendicular case head /bolt face and muzzle crown will improve the results on target as long as the other 500 variables of case ,primer ,powder and bullet are also attended to also.

 

[fiver]

I probably wasn't 100% clear on how I wrote how the front band will move some of the lead from the slightly undersized band when it engraves the lands [into places where it does fill the grooves]
when I'm talking undersized I'm speaking of about .001 undersized or around 356 on the front band.
not say 355 in a 357 magnum.
there's undersized and there is undersized.
we all talk about diameters being off and many times were are discussing .001 differences without actually putting out a number for reference.
.001 is the difference between being able to thumb seat my 410 diameter 41 mag rounds, and having to turn the cylinder to force each 411 boolit diameter round into position in my revolvers.
guess which ones shoot slightly better groups?
guess which ones I wanna carry when I'm out shooting bunnies and may have to unload the revolver a couple of times a day.

 

[Lost Dog]

Ok. I'm going to carry on in my ignorant bliss and continue to load like I have been with the rounds I cast. All with smaller front driving bands. Who am I kidding? I'm a combat shooter. Those slightly smaller bands up front also insure complete chambering when they drop from a speedloader. Guess I am happy with "Minute of Chest Cavity". And I still can get it at a hundred with my 4" M629. Good enough for me.

 

[Rick]

And then why in the world do most all SWC'S have smaller front driving bands then?

I can't answer that simply because mine don't.

I do have SAECO numbers 396 and 399 that are two diameter bullets with the front band about .005" smaller than the middle and base bands. These smaller front band allow the cartridge to lay at an angle in the chamber even in the tight tolerances of FA revolvers, when fired the middle band strikes the edge of the throat and shaves off lead. In addition to leading they where quite lucky to hit the berm, forget grouping on target. Best I can say about these two bullets is that they are not revolver bullets, at least not in my revolvers. They are the only two bullets that leaded my cylinders and leaded them badly. These may be fine in a rifle but these small front band bullets will never again see one of my revolvers.



Here they are sized nose first in a Star without lube. Notice the front band wasn't touched even though both are a mild snug fit in my FA 357 but obviously not the front band. Both lead horrible and neither shoot worth a hoot. So much for smaller front bands. If you have other SWC designs with a small front band perhaps they are of much older design, I dunno. These are the only two I have.

.

 

[fiver]

yep rolling along with what works is really the best way to go.
many of my rifles have 'what shoots best on paper' and 'what I'm taking hunting' boxes ready to go.
you have to make little compromises to have the BEST anything for a particular job or to just have a generalized load.
this is where factory's fall a little short at times.
they have to make a product to fit everything no matter fi it's 120 years old or brand new with tolerances that stack up [and down] every which direction.
so they go to the most generalized load they can muster to make that happen.

we have the luxury of being able to measure ONE gun.
make some changes to it to make it better.
then custom fit our ammo to each and every chamber to make it do what we want.
and then choose not only the projectile but it's down range performance too.
we can adjust the speed up and down, tune the barrel vibration 5 different way's, and change how we operate the thing to slightly make it perform better and better.

except that every time we change something to gain something else we lose in another area.
if you want speed in reloading you lose in hunting terminal performance and give up some accuracy to save a little time..
if you want tiny little groups at 50yds you give up something else again to get it.
if you need to whack a chunk of steel at 300yds with a revolver [and have it tip over] you have to give up the speed in reloading the revolver to get off 6 more shots in a timed event.
[or back at the guy shooting in your direction]

so we all cheat a little we look for that .001 here and that .001 there sneaking up on getting what we want ultimately but without sacrificing what we need to accomplish our goal.
the ones that write out book length or magazine length articles and put them in front of everybody are regarded as guru's.
the ones that just do it and try pointing others in the direction they took so they can learn what they need to know to make it happen [again and again] and make something else happen in another event get overlooked.
writing responses to stuff is gonna be based on the back round of the writer and what he needs to accomplish his ultimate goal in the shooting game.
I tend to write more from the perspective of shooting rifles as fast as possible while maintaining accuracy
with naked lead.
Rick's and Jim's is from ultimate long range accuracy in a revolver.
how we get there is quite often accomplished through many of the same manipulations and 'extreme' measures [to some]
to us it's routine every day stuff to sweat out consistent bhn, waiting for boolits to harden, sweating oil dump from a lube, and finding out if .0005 is gonna help or hurt.