38 Special at 50 yards (again)

[size=13]Background:[/size] 
[size=13]With either my Lyman 358311 (165 gr RN) or Lyman 358212 (148 gr RN), I get boringly repeatable 2 ¼ inch groups at 50 yards out of my Model 14, needing only to push these bullets at 720 f/s.  [/size]
 
[size=13]Objective:[/size]
[size=13]Find an accurate, fifty yard load with a bullet that cuts clean holes using a Smith and Wesson model 14.  [/size]
 
[size=13]Set Up/Process:[/size]
[size=13]Ransom rest mounted identically for all sessions.  [b]One range session per velocity[/b]. Three different velocities total. Two representative DEWC bullets (so six days all of which were identical regarding weather); benchmark velocity that I use with my accurate RN load (720 f/s), an intermediate (840 f/s) and a third (950 f/s).  One group is six rounds (one cylinder).  Note:  The highest velocity matches the spin rate (36,000 rpm) of the 14 inch twist Cold OMM/Python travelling at the same speed as my accuracy load (720 f/s).  Starting from a cleaned gun and using my standard RN load, shoot enough "settling in" groups to confirm the gun is settled in the rest and also shooting the typical 2 ¼ - 2 ½ inch group.  This required 2-3 total cylinders (2-3 groups).  Look down the barrel without touching the gun to verify no leading.  [/size]
[size=13]Same press, same dies, same brass (Remington match), primers.  Note: To get to the third and highest velocity I needed to switch from BE to WST.[/size]
 
[size=13]Test:[/size]
[size=13]With two DEWC's of identical diameter and hardness, I loaded these bullets up to increasing speeds until I achieved a similar spin rate compared to 720 f/s out of a 14 inch twist.  Out of my 18 ¾ twist Smith, this would be about 950 f/s.  Shoot 3-5 groups of six for each velocity and each bullet.  The two wadcutters are the Magnus #501 (same hardness and diameter as my RN load but unknown lube) and my Hensley & Gibbs #50 (same hardness, diameter and lube as my RN load).  Three different velocities, two similar DEWC bullets.[/size]
 
[size=13]Results:[/size]
[size=13]No difference between the two DEWC bullets.  Starting out at 720 f/s, groups were around 12 inches in diameter. The intermediate load gave groups that fell to about 6-7 inches.  Groups from the 950 f/s load were 5-6 inches in diameter.  [/size]
 
[size=13]Notes:[/size]
[size=13]Clearly, I'm not going to get there with a solid DEWC at reasonable velocities and if this is representative of what a ballistics engineer would predict, then a solid DEWC cannot give an accurate, 50 yard group out of the 18 ¾ twist.  Does this suggest that, since this is the same spin rate as one would get from a 14 twist at target velocities that the solid DEWC was NOT used by PPC shooters for their fifty yard stage?  Maybe they only ever used HBWC's?[/size]
[size=13]How different would a HBWC perform; not because of the "expansion of skirt diameter" theory, but because it is perhaps more stable?[/size]
[size=13]I haven't any SWC design molds so I don't know for sure but perhaps this design gives the required accuracy with cleaner looking holes?[/size]
[size=13]Through measurements of case ID's, OD's, bullets, loaded rounds, I can say that the case always expands the full amount of interference.  The bullet does not swage down when seated.  I used match brass which has a .010 wall and no internal taper for the full length of a DEWC.  This might not be the same for standard brass which has a taper and about a .011 wall thickness at the mouth).[/size]
[size=13]Have I done enough to confirm the statement that target velocities will, under no circumstances, permit an accurate, fifty-yard group out of an 18 ¾ inch twist (six inch) barrel when using solid, full wadcutters?[/size]
[size=13]This is what happens when I suddenly find reasonably priced SP primers and only a revolver to shoot. :lol: [/size]

Breech,

I've always preferred HBWC for accurate 50 yd loads in a 38 revolver.  I only shoot DEWC indoors at 50 ft.  So I don't have expert advice to offer.  My problem has been working up loads for 158 gr LRNs that come close to factory ammo in accuracy at 50 yds for Distinguished Revolver matches.

That said, you seem to be making two assumptions that I'm not sure will pan out.  The first is that the DEWCs need to go FASTER than your LRNs in order to stabilize.  The second is that spin rate is the secret sauce for small groups with what's ballistically a lead barrel flying through the air.

In my wheel guns (1 Model 14 and 2 Model 10s), wadcutters group at speeds that are much slower than LRNs.  And for my wadcutter ammo, powder weight is the most important variable.  With LRNs, I've found crimp and other variables play bigger roles.  

So, I'd suggest going back to the Ransom Rest with a bunch of ladder loads that start way down at or below the published minimum charges and see if a recipe for accuracy reveals itself in the ridiculously slow range.  If you're using Bullseye as your powder, I'd suggest a starting point at something like 2.5 grains and work my way up to 2.9 grains.  For many revolvers, there will be a sweet spot around 2.7 grains.

Once you find a load that groups decently, re-test that particular load recipe by shooting groups using individual chambers.  You might find that chamber 1 will hold the x ring, while chambers 2, 4 & 6 are only capable of holding the 10 ring.

After that, you can set up your chronograph and find out what speed their going and calculate the spin rate.

Regards,

David

I don't think faster helps. The aerodynamic loads go up with the increase and you don't have enough twist to keep up with it.

HBWC is longer and nose heavy. Inherently more stable.

PPC, I think most I've seen have custom heavy fast twist barrels.

Well I never thought to go slower.  The idea to duplicate the rpm of a successful load came from a local smith whos advice I took, to be perfectly frank, because he did such an amazing job refurbishing my Parker.  Not a useful pedigree but I got locked into this thinking.  Anyway, slower it is.  Thanks for the tip.

PPC, 1-12 twist barrel, 148 HBWC’s. Joe Leinenger.

Sandbagged.

CRITICAL WITH THE 148GR DEWC BULLET IS BULLET DIAMETER. YOU NEED TO TRY DIFFERENT DIAMETERS.  FOR EXAMPLE .355, .3555, .356, .3565. YES, YEARS AGO THEY MADE 5/10000 SIZING DIES CALLED "SPLITS". THEY'RE HARD TO FIND BUT WORTH THE EFFORT.

JIMPGOV is right, well in my experience. Bullet diameter was crucial to get those DEWC to shoot out of my 1911’s. Lotta work. I like shooting more…….148hbwc
Jon

710 fps has been the forever standard for HBWC.  In my OMM factory ammo was Xring 50 years ago.  Sometimes even offhand.......

If you can find an older or retired PPC shooter in your area, you might want to see if he or his buddies have any Star Master Match 158SWC left over that you can score, this is the stuff that was sought after back in the day. It was used for Police Distinguished matches all the time, and I know that it won several Distinguished Matches (including Nationals), and held the record for the 25 yard Service Revolver match until they changed the course (420/37x, I believe). It tended to be a little dirty with leading, but you were only shooting 60 rounds, (although 24 were from 50 yards) - high 590s were not unusual with this stuff.

The factory new was all in Starline Brass in the white box, but the also sold remanufactured in a blue box. I had laid in some bullets to try to use as Star was closing, but never got around to it, continuing to use what loaded ammo I had/could score from others, until I stopped active shooting of PPC.

I STILL HAVE SEVERAL K OF THE STAR 158GR SPECIAL MATCH BULLET. NONE BETTER FOR ACCURACY.

MY BEST DISTINGUISHED REVOLVER ( IN PPC) WAS 596 OUT OF 600. MY BEST SERVICE REVOLVER WAS 480-43X. BOTH OF THEM WERE SHOT WITH THE STAR SM BULLET.

I have 2 interesting take-aways for model 14 loads since my study from years ago: swaged 148gr HBWCs always ran great with 2.5gr BE, then I discovered that the REM-UMC 158gr LRN was accurate at 50 yards.

In my testing from years ago, I figured that I had too much case volume with 158gr projectiles and BE powder. I never tested it because there was plenty of the REM-UMC available. 

I ended up getting an ammo can full of swaged 158gr LSWCHP and started loading those backwards like a wadcutter with 2.5gr BE and those are plenty accurate. Far more accurate than anything 158gr that I tried to develop years ago.

So, was it the swaged bullet that my 14 likes or is it the smaller case volume? 

If I had a need to develop a new load, those would be the answers I would look for.

Perhaps not science, but I am sure I have fired and loaded many hundreds of thousands of .38 HBWC over the decades. Many fired from stock S&W barrels with 1:18 twist, and many from custom barrels of 1:10, 1:12, 1:14 twists. Good loads shot well out of good guns with clean barrels, regardless of the twists with velocities in the 720-770 fps range. 

I did find that 148gr DEWC would also shoot well out of the same guns if driven slightly faster to the 770-830 fps range. My "guess" is that DEWC do not obturate as quickly as the HBWC, so the hotter load may have caused the bullet to get a better, quicker seal in the throat. I know that the Bayou 138gr BNWC shoots best in the 860-880 fps range.

Regarding low charge volumes and large case capacity, powder position in the case matters significantly to velocity. Take any low volume case load and shoot six shots over a chrono, tilting the muzzle upward and lowering to horizontal slowly before shooting. Record fps.

Then do the same with muzzle pointing downward before each shot then slowly raising to horizontal before each shot. Record fps.

Both will have fairly good deviations between shots fired in the same manner, however the velocity difference between the two tests will be significant. Do not be surprised in the avg fps delta isn't 60-100 fps different, depending on load, powder and projectiles.

Interesting. About twice a year I function test my wife's night stand gun which is a 4" Taurus 66 .357 that I load with 38 Special Federal HST). It shoots so well I'm curious how it would do with HBWC. I've never sat down with a sandbag to group it at 25 yards. Local indoor range is just 25 yards. Will order some HBWC & see what it does next range day. Trigger is decent, especially SA.

I loaded some cast 158 SWC backwards today with 2.8 WST. Left them sticking out about .05 for the crimp to bite. Used the PE DEWC expander, and I could push them in with my thumb. Would have been nice if the top, now bottom, lube groove was filled.

At some point I'll try them out, probably for function in the 'gravel pit' before trying them on paper.