Why some wide groups?

[Will]

I have a 38spl (Colt police positive 4" bbl) I have never been able to get it to shoot a decent group with a reduced load. I've tried many boolits and many powders but if the vel gose below 800fps the groups open up to 6" or more. It will shoot anything into 2" from 800fps to +p loads. My 44 mag Blackhawk seems to have the opsite problem a 175gr 1/2 jacket driven at 1400fps will give 12" groups at 50'. Is this just a problem with these guns or has anyone else had similar problems?

I've been trying to work up a plinker in the 38 for my grandkids but so far no luck.

Will

[BABore]

I would start by looking to your gun's groove and cylinder throat dimensions. Then I would look at alloy hardness. You could be looking at a situation where your fast loads have enough pressure to bump up your boolit to fit your gun. If your using the same alloy, at less pressure, then it will not happen. Size your boolits to your cylinder throats. Make sure your throats are slightly larger than your groove diameter. Using a softer alloy at low velocity. You will likely have to use a lube that is both softer and of lesser quality (slickness) at lower velocity.

[Cherokee]

What BABore said, except I use the same hard lube for low to high velocity shooting with no leading.

[Larry Gibson]

Try some Speer/Hornady HBWCs over 2.7 gr Bullseye. Seat bullet almost flush and use a taper crimp or a very light roll crimp. If accuracy is poor with that load then look at what BABore says; softer alloy, bullets sized to throats and soft lube (Javelina or any 50/50 alox/beeswax lube will work).

Larry Gibson

[beagle]

The HB WC is a good idea. That will allow the skirt to bump out and take care of loose tolerances. You didn't say what diameter you were sizing to or anything about the chamber/barrel dimensions. Back in those days, dimensions were all over the place. A little tweaking on diameter may pay big dividends on group size./beagle

[44man]

Here we go again----a complete lack of understanding of the relationship between velocity and twist rate. Some of you shoot revolvers like smooth bores! Or forget they are rifled.
A 175 gr .44 boolit???? What is that about? The Ruger will not even start to group until 240 gr's. That 175 gr boolit has to be shot dead slow, NOT 1400 fps.
You must accept the fact that pipsqueek loads will shoot bad if the gun is not rifled for the load or boolit.
Guys work like mad to match loads and bullets to rifles and their rate of twist but completely ignore this with a revolver.
How hard is that to understand? [smilie=1:

[kir_kenix]

twist rates are very important, but there is no reason he shouldnt be able to get a .38 spc to shoot in the 600 fps range. I dont believe that his twist rate is the problem in this case. I would also wager that his boolits are either undersized, and or too hard. I would try some very, very soft WC boolits sized to the cylinder, over a light charge of fast burning powder (bulseye or equivelent). I like LLA, or similar lubes on my very low pressure low velocity handgun rounds.

The .44 may very well be a twist/rpm rate problem, but I would try the same steps that you are going thru with the .38 before giving up on powderpuff loads.

There is a ton of good advice here, and I'm sure you'll get somewhere with it. Good luck, and I hope you can get that Colt shooting for your grandkids!

[missionary5155]

Howdy Will
I have had several Colt Police Positives (still 2 sitting about) . As said above.. Boolits larger than the throats. My personal favorite is a 160 WC cast soft with 3.5-5 grains Unique. If the Colt (or whatever 38) has fat throats I increase diameter. Check "Beagling" ... works just fine. So does Bumping in an appropriate diameter sizer.
I never had a hollow base mold and have not used them But they fulfill the NEED to seal the throats.
So far my 38´s have had smaller barrels than throats. But if I ever own one I will open the throats.

[Will]

Here is what I'm doing. My grove dia is .357 throat is .358, Boolits are 148gr WC and 105gr SWC, Powder is 3 1/2gr unique. This should give about 600fps and 670fps. Metal is WW + 1% tin, sized to .358, Lube is 50/50 alox/beeswax. Shot from a hand rest at 50ft the group with 148gr was about 5" the 105 4shots were 7" and one off the paper. I got the load from Lyman #45 using similar weight boolits. With 158gr 358156 and 5gr unique 900+ fps it will go consistently under 2". The 148gr WC will also go under 2" when pushed over 800fps. What am I doing wrong?

[Hardcast416taylor]

I`ve got a 4" Colt Trooper Mk3 from my law enforcement days. I had a mild load with 148 gr. Hornady bullets infont of 3.3 gr. of either HP-38 or Win.231 or Red Dot. It was a very accurate load to shoot and teach new shooters to shoot. I even used that load to help turn keys and other jail personnal when they had to qualify each year. The 44 problem may be solved by going up to a 200 gr. weight to better suit the twist in your barrel. :castmine: :Fire: Robert

[fecmech]

I got the load from Lyman #45 using similar weight boolits. With 158gr 358156 and 5gr unique 900+ fps it will go consistently under 2". The 148gr WC will also go under 2" when pushed over 800fps. What am I doing wrong?

Some loads just don't shoot! The classic 2.7-3.1 grs of Bullseye is the standard WC target load would be what I'd try if you want something less than the 800 fps load.

[44man]

Here is what I'm doing. My grove dia is .357 throat is .358, Boolits are 148gr WC and 105gr SWC, Powder is 3 1/2gr unique. This should give about 600fps and 670fps. Metal is WW + 1% tin, sized to .358, Lube is 50/50 alox/beeswax. Shot from a hand rest at 50ft the group with 148gr was about 5" the 105 4shots were 7" and one off the paper. I got the load from Lyman #45 using similar weight boolits. With 158gr 358156 and 5gr unique 900+ fps it will go consistently under 2". The 148gr WC will also go under 2" when pushed over 800fps. What am I doing wrong?

You are not doing anything wrong with the faster loads. Those are what the gun likes. You just can not take one boolit and shoot it at every velocity you can think of.
If you pick one boolit and work loads from minimum to max, each will get accurate at ONLY ONE LOAD. You need to do this with each boolit. As you have found, the heavier boolits need more velocity to spin up.
Load a heavy boolit in the .44 and you will find accuracy just below max but try to load the same boolit at 700 fps and you will get better accuracy batting it with a tennis racket.
TWIST RATE AND MATCHING VELOCITY are fixed for each boolit.
Why do you think I get groups as small as 7/16" at 50 yd's and under 1" at 100 yd's from my revolvers? You are shooting 50 FEET! I don't even know what that is! I shoot revolvers to 500 meters (547 yards) for fun and hit steel.
Believe it or not, the .357 CAN shoot decent way out there.
You are trying to make something work that is not possible.

[runfiverun]

change your 3 gr unique load to 3 gr clays or b-eye.

[mooman76]

You could try a softer bullet for those low speeds. It may bump up better.

[Larry Gibson]

As mentioned, change to 2.7-3 gr of Bullseye. I really don't care where you got that light load of Unique it is too light to ignite and burn efficiently. Powders of different burning rates and composition need a certain pressure level to burn efficiently. You are not getting it with that load. Go to Bullseye.

Ok, we know what the throats and barrel sizes are but what size are the bullets? What is the alloy? Best size for the bullets would be .359". Best alloy would be close to dead soft lead at 7 BHN. I've found the Lee 105 gr needs to be pushed to 1000 fps or so for best accuracy but will shoot into 2" at 50 ft at 700-800 fps. The 148 HBWC cast very soft and at .389" is your best bet for accuracy.

Larry Gibson

[Will]

I see a lot about twist rates vs weight and type of boolit and speed. Is there any formula to determine what will give the best performance or is it all trial and error to work up a good load? Is there a table anywhere that tells the twist rate for a particular gun or some way to determine what it is?

[Wayne Smith]

For your .38 get swaged, dead soft boolits and try shooting them at the low speeds. Swaged boolits are close to pure lead. If they work, go no harder than 50-50 ww/lead for the low speed shooting.

Listen to Lloyd about your 44!

[Will]

I only have a few lbs of pure soft lead. How much WW do I mix to get a soft boolit that still wont lead at 700fps? Would 50/50 be right and should I add tin?

Will

[mooman76]

If you are going to cut your WWs with soft lead to make them softer, it doesn't make any since to add tin which will make them harder. As Wayne said mix WWs with soft lead to make softer bullets no more than 50/50 in fact you could even go softer like 75/25 or pure lead. There is no magic formula sorry to say. There are a billion combinations of powder and bullets and alloy you could try to find what you want. You may find it or may not find it or it even might not exist as far as your particular gun goes. You might even want to try some round balls for plinker loads. they may or may not give you what you want. I've been meaning to experiment with some light RB loads as plinkers to see how they do.

[44man]

Just pick a powder and work from minimum to max. The fast powders should be worked in very small amounts. Somewhere you will find some accuracy. If you don't, move up to a little slower powder and do it all again.
If you just pick one load from a book, you will be disappointed 90% of the time. With a powder like Bullseye, you might be off a tenth of a grain. With very slow powders, a tenth of a gr will not change things much.
The first thing needed is boolit fit to the throats and a little larger then then groove to groove size.
You can soften or harden and try all kinds of goofy tricks like turning a boolit inside out in the barrel or turning it sideways when you shoot it! :bigsmyl2: But if you don't follow the rules you will never get an accurate load.
What softening a boolit does to make it match the twist rate escapes me completely. Get too soft and you will spend a week removing lead from the bore. Speed up the dead soft boolit and it will skid down the bore and open the land marks so gas will cut it.
The gas check was designed long ago when softer boolits were common and to reach a higher velocity the base had to engrave the rifling without skidding.
Very fast powders increase the velocity very high right in the cylinder so the boolit hits the forcing cone hard and fast. A soft boolit can slump like putty and actually squirt lead out of the gap. You no longer have the boolit you started with, just a slug of lead and a bore full of lead. As you increase velocity with ANY powder, you are better served by making the boolit HARDER. So be aware that just working loads with a dead soft boolit will make it fail before you reach a max load with each powder. You might miss the super accuracy from that boolit because you ruined it.
You must learn the mechanics of the revolver and how it effects boolits before you will have the accuracy you want. To just ignore this will have you giving up a good boolit or turning the gun into a safe queen.
I for one, will never tell you to soften boolits because they are not accurate. If the boolit is undersize and you want to bump it up for a better fit, be aware you have also ruined your accuracy from the git-go.

[Larry Gibson]

I only have a few lbs of pure soft lead. How much WW do I mix to get a soft boolit that still wont lead at 700fps? Would 50/50 be right and should I add tin?

Will

Will

You are working off some misinformation and over thinking this problem. Pure lead can be shot upwards of 800-1000 fps without leading. It is not tin nor antimony that prevents leading, it is the lube. Cast your bullets of pure lead and lube them. Do not size them. Try those "as cast" bullets over Bullseye as I've mentioned.

Larry Gibson