On the subject of bullets. This is not like deer hunting where you go buy a Remington rifle and a box of bullets and go. These rifles are all individuals, a bullet, powder, lube combination may work in one rifle and perform badly in another rifle just like it. You have asked for bullets but we don’t know the size of your bore / groove diameter, the twist of the barrel, or what kind of throat is in your rifle. All of these will have to be taken in to account to get the rifle to shoot to its full potential, that and a lot of shooting and tinkering.

40 Rod

Seriously guys, maybe set_trigger hasn't considered all these questions like length of throat, bore & groove and diameter, twist of rifling, and etc, we know without these figures we're just peeing in the wind.  I consider myself lucky and a little embarrassed to say I have without counting about ten different 32 moulds and I've also been swaging bullets for sometime, looking for the perfect bullet that does not exist.    leadball

Set_Trigger
1.5 inch for 5 shots at a 100 yards might be good results. Do you set out wind flags when you shoot, use a spotting scope to keep track of mirage and shot placement, shoot in the same wind condition for each shot or just hold center and blaze away for 5 shots? Do you keep records of your shooting sessions? What powder and charge were you using, primer, cartridge case, fixed or breech seated? What bullet alloy were you using, what lube, did you get any leading? All those and your shooting technique make a huge difference in rifle performance. I’m not trying to be critical, this is not a simple shooting game. Perfect bullets (or as near to it as you can get) are a major component. The choice of cartridge case is important but so are the other factors I stated.

You mentioned you can shoot 1/2 inch, 5-shot groups at 100 yard using jacketed bullets. Compared to cast bullet 32-40’s your jacketed stuff is like shooting down a string. If you aren’t closely watching conditions, a gentle breeze can move your 32 cal bullets around enough to open up a an otherwise good group to 1.5 inches. This brings me back to my initial post, the bullet. I have helped a few shooters get started by casting some bullets for them but a 100 is a lot of extra casting, a 1,000 is pretty much a season’s worth for me also and I shoot three different schuetzens. You might try posting in For Sale/Trade that you want to purchase 1,000 (or number of your choice) nearly match-grade cast and lubed bullets. With a phone conversation or a few emails, you can likely determine if any takers are worth considering to fill your order.
Good luck and I hope you find a source of good bullets.

The biggest problem that I can see is your using store bought bullets. Pre-cast bullets come in basically in two forms. The first are hard usually Lyman #1 or linotype both are too hard. I am going to go out on a limb here and tell you nothing good happens when you add antimony to your alloy in schuetzen. The second set of bullets are cast of pure lead on 40:1 lead tin mix these are meant for BPCR and are usually found in the .40 - .45 cal range. 
  For a Darr barrel you want somewhere in the 25:1 to 30:1 lead to tin alloy. Unless someone has damaged the barrel that rifle should be capable of shooting min of angle or better.

40 Rod

You might try Montana Precision Swaging for cast lead bullets.  They have a 32 40 slug that is a Pope style bullet.  The bullets come lubed with SPG lubricant.  I have fired these out of a Stevens-Pope .32-40 with black powder both muzzle loaded and breech loaded.  They will work until you learn how to cast your own. Not sure what the hardness is for these bullets.  20:1 25: or 30:1 lead bullets is what you really want.  Lead bullets DO NOT wear out a barrel.  Harry Pope fired 125,000 bullets (or about 1.75 tons of lead) thru his favorite rifle (barrel #150).  Ray M. Smith had that rifle given to him by the Pope family and it still holds a tight group - 1 MOA.

.32-40 Bullet
CB-32-200FN   .32-40  200 grains Sized .323 Flat Nose   $15.25/50

Montana Precision Swaging, Inc.
P.O. Box 4746
Butte, Montana 59702-4746

Phone: (406) 494-0600
E-mail: MtPrecSwaging@bigskyhsd.com

Gary
Ft Wayne, IN

I use bullets run through a .312" sizer in my .308" barrel...the sizer barely touches the base band on my modified Lyman (formerly gas checked) mold, and I'm mostly using it as a grease pump.  The rule of thumb is to use a bullet about .001" to .003" larger than the groove diameter of your barrel, when working with soft lead.  Try the larger bullets, they may work quite well...especially if the throat of your barrel is a bit on the big side.

David Kaiser
Montezuma, IA

Set Trigger

A good starting load for your Darr barrel is 14.2 grains 4227, WWLR primer, if using a flat nose bullet do not exceed 1.00" in length,.322/323 diameter (as cast), cast 1 part tin to 19 parts lead (1/20) alloy, breech seat .050". Any of the popular bullet lubes will work well. Start at 100 yards to refine your your powder charge. By all means use some sort of wind flags, preferably 3. Don't be anxious to make any changes to the load, each single shot rifle seems to have its own personality, and may need to be held with more or less shoulder pressure, more or less pressure on the pistol grip, etc. 
Other problems may be that the barrel is very badly leaded or the throat or the muzzle crown has been damaged. A damaged muzzle will usually reveal itself after 10 to 15 shots by a uneven powder star on the face of the muzzle.  
Regards, B.W.Darr