Cylinder and barrel diameter/specs for the governor

[Squib]

my main question is what is the bore diameter, and therefore what size JACKETED bullet is optimal.  .451, .452, .454... etcetera.  I CANNOT find the answers online after looking for three days after work.

my secondary is what is the diameter of the cylinder "charge holes" or whatever that empty space is, so I know how much "side-space" is available to melt lead bullets with blow-by. 

If it's much more than the bore then I've either got to accept substandard accuracy with jacketed bullets or go with really weak loads with really soft overbore lead bullets to get accurate.  it shoots standard acp innaccurately, colt I haven't yet loaded up (will this weekend if I can get the optimal bullet info though).  it shoots factory shot shells decent enough so no complaint's there.  ps- acp has recoil in a light revolver.  I always shot it out of steel semis before and thought it was a joke... scandium revolvers DO have a drawback! 

[jimster]

I was handling one of these S&W governors and was also wondering the same thing.  I like these better than the Taurus ones.  Anyway, after thinking about it, I figured the only way I would know for sure is to actually buy one and measure it to find out because I'm not so sure every one is exactly the same anyway.  Since you already have one, maybe you can find a way to measure it, drive a slug through it, or measure it best you can with a caliper.  After thinking about it some more, I figured if I were shooting .45 bullets through anything, I'd probably use another gun and I'd probably just be shooting shot shells through the governor anyway.  I guess you need to just measure the holes somehow and play around with it, you might have to go with a special size lead bullet if it's too far off, and if it's too far off they don't make too many sizes of jacketed bullets so you might be out of luck there.
Good luck and let us know what you find on the size of the cylinder holes and barrel. 

[reliquary]

I have a Governor, but no way to measure the throat or freebore dimensions.  Mine shoots acceptably well with .452  and 200 SWC in the ACP case, but the .454 ~250 Keith in the Colt case is noticeably more accurate.  For whatever that's worth.  You may just have to tweak your loads?

[reliquary]

make that " jacketed ball and .452 200 SWC"

[Squib]

so far all I've loaded up in COLT is starline brass, o.a.l. 1.590, 8gr Winchester 231, Hornady 185gr XTP.  the weather sucked last weekend so I didn't get out to test yet.  those bullets are .451 or 4515, can't remember at the moment.

yes I have calipers and know machinists who could "poke-around" on all of that stuff thoroughly, but I'll not have scratches and such on a brand-new gun just to check that stuff out.  I have zero safe-queens but I'm ocd about maintenace/hygiene.  that's right, I practice gun hygiene 

that load (.2grs more powder than the 200gr Hornady XTP starting load but with a 15grs lighter bullet) should be no worse recoiling than a .45 acp and probably less.  I believe the lower m.a.p. and increased "hollow" (air in the case) will take the snappiness out of the round.  If I'm wrong I've still got a +P acp level load with MUCH less pressure and better accuracy potential though so it's all good.  ps- those bullets with no crimping groove are harder to load securely than I though. 

[Squib]

the 45 colt loads are SO FAR not more accurate, but I'm not done experimenting yet.  the +p .45acp I used was hitting 1-foot gongs at 25yds but not in a consistent group by any means.  I had others try it also, same for them (it WILL stay on a torso sized target but all over it).  same with some .45 colt too. 

.410 shoots good, just like before.  it stays on a text book at (approximately) 10 yds and it's a thick pattern generally, but high.  I suspect that the pattern "climbs" as the gun is in recoil.  like wing-shooting, there is a lead and swing-through to keep all the shot on target as the gun is "fanning" the shot out horizontally.  if I had banana hands I suppose the issue would be resolved and all the shot would stay centered???  I don't have large, strong hands though, and for me it tends to start just above dead center of my aim and continue up 6-8'', so I think that if I aimed at a chin the face would take it all. 

the pdx1 performed well.  the discs seem to stay close together within 15 yds.  at five feet away they make a BIG ragged hole and keep the pellets right with them.  the pellets spread quite a bit out at 15 yds, some would miss a skinny man or just nip him.  the pellets were deforming a bit to horribly upon impact with a math book, the discs were going through in a straight line instead of tumbling and were usually staying intact.  some deformation like stipling or taking on a porous or warped texture but the shape stayed circular except for a couple that turned into a pac-man shape, those were the two (2 discs out of 12) that yawed on impact and went in edge first.  I believe the discs would have come close to exiting the book if it weren't draped over some sort of rubberized material that is quite resilient.  the book was shredded severely in four shots, and I feel that it would do the same to flesh within 20 ft.  I'm going to keep trying to get the accuracy up with .45 colt but I am happy with the shredder effect, it does that damn well.

[Squib]

for what it's worth I had some loads worked up to 9.6 grs of winchester 231 with the hornady 185gr xtp, fired out of starline brass, with federal large pistol (non-magnum/standard) primers.  neck tension was upped a bit over secure but NOT QUITE enough to "bite into" the jacket.  these bullets have no crimping grooves and I chamfered the mouths well.  these still showed no signs of overpressure on the primers (no craters, no flowing, no drifting/eliptical indentation, no flattening, no backing-out, no frame-stamping, etcetera), nor the cases (virtually no swelling, possibly NONE, cases coated with powder residue {mostly on 1/3 of the case all the way down to the head}, loads were still weak and lacked penetration - - - BUT SHOWED BETTER ACCURACY.  I think that with careful and deliberate shooting a 6'' group could be achieved at 25yds sitting but no better (I almost got that standing a couple times).  I could keep going up but then I'm going to split cases trying, the 45 colt is still a ways off from being full enough to get a good, clean burn.  Also, I've noticed that the .45 acp brushes I have are all REALLY LOOSE when cleaning it out after a range session.  so even if I don't crack my brass and manage to hold that gun rediculously tight during recoil (to minimize obturation within the long cylinder) the barrel will allow blow-by within the rifling.

180 GR. CAST LRNFP  Winchester  231  .452"  1.540"  6.0  838  6,500 CUP  8.2  1087  13,900 CUP       
200 GR. CAST LRNFP  Winchester  231  .452"  1.600"  5.9  761  5,800 CUP  8.0  1002  13,800 CUP       
200 GR. HDY XTP  Winchester  231  .452"  1.600"  7.8  956  11,000 CUP  8.7  1048  14,000 CUP 


so with 10grs even, I'm over the load by about a grain (reasoning that I can use 9grs just fine with a lighter bullet with no crimping groove) and still probably under 20,000.  It's no gun buster but still I don't want to flame cut a scandium weapon, or blow a primer out from an unsupported case blowing out.  If I want to get better accuracy I'm going to have to shoot very carefully tailored; oversized, cast bullets of varying hardness to eventually get it right, round ball for close range only, or saboted bullets from a shotshell or .450 mongo wildcat custom brass.

lesson learned: just shoot 45 acp for light bullets, colt for heavy, and give up on velocity (and groups)  I want to eventually give it a shot with .454 bullets in the 200-220grs range but that'll be a long time from now, I'm back on .357 Magnum again.  Later.

[reliquary]

Keep trying.  My Governor is acceptably accurate with some "generic" loads.  Maybe yours is more finicky?
 
Mine likes FMJ factory ball and the .452/200 LSWC handloads with around 6 grains of Unique...will keep both those in 4-5" at 25 yards from a rest.  In .45 Colt brass, it likes the .454/250 LSWC with a little over 8 grains of Unique, and that groups a little tighter than the ACP loads.  That's about as well as I can do with any pistol, these days.
 
FWIW, I couldn't get any data from S&W, either.  They did tell me that the barrel wasn't generic, the Gov frame wouldn't accept any other Smith barrel, and they had no plans to offer any barrel lengths than the one it now has.  I thought (briefly) about playing with different barrel lengths but have since lost interest.