Shooting cast in the S&W 500, questions .

[Joe C]

Hi all,
I'm looking for some response from those of you that have some experience in shooting cast bullets in your Smith
500's .

I have measured the throats, (.4997" ) and bbl groove (.5015-5017" ) on the gun i have , a JR 500 , that i pickup up a few weeks ago.

If i stick with a light load , 14 gr Trailboss , and 475 gr JR design long range bullet at 800 fps , i don't get any leading .

Pretty much anything else, 900-1000 fps + loads, and above , and i start getting leading starting about 2" down the bbl.
with as little as 10-15 rounds .
These are wheelweight ,and wheelweight/ 25% pure lead, bullets .

In reading some of the load info that John had written , he mentions using a plastic wad , (ldpe maybe) on top of the powder to cut down on leading .
I have used these in the past in some of my BP loads in my 45-90 , 45-110 .

Conventional wisdom says that i have to open up the cylinder throats to at least .5015" and i was wondering if anyone else has done this , and how it worked out for you .

I can't get too carried away with the throat opening , the cylinder has a pretty tight chamber , i did load an as-cast bullet
of .502+ diameter and it did chamber ok , but i doubt you could go any larger .

I have a .5015" throater from Pacific tool and gauge waiting for me, I just want to make sure i really want to use it ????

I am also concerned as to what effects opening up the throats to .5015" would have on the use of jacketed bullets , as those run right at .500" diameter .

I really don't plan on shooting jacketed , but somewhere down the line , someone else is going to end up with this revolver.

thanks


Joe

[44man]

Throats are smaller then groove, becomes a leading master. Your gun has over large grooves too so once the throats are reamed, you need at least a .502" boolit. Throats will be best at .5025" or .503".
I imagine your gun has five grooves and lands so do you have a good measurement?
It will also let jacketed shoot better because you are smaller at the throats then they are, why size jacketed?
Good luck finding a mold that casts at least .502"
My BFR in .500 JRH has .500 groove, .5015" throats and I use a .501" boolit.

[Joe C]

44man .

Smith went with 6 lands/grooves in the 500 , so i am pretty confident in the measurements i got when i slugged the bore .

I have done it several times , just to make sure i didn't get an odd reading .

I know i am going to have to open up the throats, I was just curious to see if anyone else had opened up the throats in their guns.

I think before i do anything , i am going to check with S&W to see if maybe this barrel might be a bit "out of spec " and if it is , get them to replace it .

Joe

[44man]

Good to hear S&W went to six. But you still need throats larger then groove. You can lap with a slotted rod and fine Emory cloth until a boolit just slides through. You still need a .502" boolit.

[bigboredad]

Tom at accurate molds can cut you a mold for your barrel thats not a problem but you might have to wait a whole 3 weeks

[Joe C]

I actually have a couple molds that cast a .502+ bullet, so that shouldn't be a problem .

I'm curious why the leading starts about 2" down the barrel ? ???

The gun has a 5" bbl . 1/10 twist .
I thought if it was "skidding" because of the faster twist , it would show leading at the forcing cone area .

Joe

[cainttype]

Check for a constriction at the barrel thread/frame junction. If you push a slug all the way from muzzle to forcing cone and feel resistance there, you have a common contributer of the type of leading you're describing.
If so, you can experiment with alloy and pressure changes. You might also research "fire-lapping", but take your time.

[5.7 MAN]

My JR 500 has tight throats .499.

[nhrifle]

The throats might be the issue here. I read the opening post here a few times, and the one thing that is sticking with me is the leading starts partway down the barrel. Before I removed any metal (trust me, it's a bear getting it back where it was when you took it off), I would look at the lube you are using and how you are applying it. I will probably be cast as a blasphemer for saying this, as lots of shooters don't like any moly in their bores, but I have used Lyman Super Moly in all of my high pressure loads and have never had any leading. When leading is as you have described I have always attributed it to lube giving out.

I may be wrong on this, but it is worth looking at before you do something you can't take back.

[Master_Mechanic]

44man nailed it, I had a 629 lead in the exact spots your talking about, throats were undersized. You can use all the lube you want and its not going away. Open the throats up and your problem will most likely go away.

[jmort]

"Good luck finding a mold that casts at least .502"

You don't need luck, just have Tom at Accurate make what ever size you want.

[ole 5 hole group]

I have a JR 500 that had tight throats just like yours. I had the throats reamed to .5015 but I was in contact with another individual who had his JR reamed to .5020. We both shoot 0.501 cast with no leading and accuracy is pretty good - 2 inches at 100 yards, sometimes a little smaller, sometimes a tad larger - rested and scoped of course. Revolver can probably shoot better but I can't consistently hold that beast to shoot better consistent groups. These are 5-shot groups and I have done under an inch several times but I've also shot bucket sized groups on occasion as well.


Mine also had a cylinder gap problem, as the cylinder would bind up after 20 to 50 rounds - sent it back to SW and they opened the cylinder gap up to .006" and it has never caused me a problem since.


I went to VV powder - mainly N110 & N120, as IMR-4227 and AA1680 shot just a mite dirty except at max loads and a flack of crud sometimes got under the star when loading/unloading and that would bind things up a bit until I figured it out. H110 is way to snappy for full-house heavy loads IMO.

[44man]

"Good luck finding a mold that casts at least .502"

You don't need luck, just have Tom at Accurate make what ever size you want.

Entirely true, best you can get. I made my own mold for the .500 JRH for my BFR. 440 gr WFN.
Throats are .5015 and groove is .500, my boolit is .501".Attachment 117083Group at 50 yards working loads. 29.5 gr of 296, Fed 155.
Throats need reamed or lapped if too small.
The S&W should not be shot at 800 fps. Twist will not handle it.

[Joe C]

Thanks for all the replies.

To answer a couple questions / comments.

The lube i am using is LBT blue, soft lube .

When i slugged the bore , did it several times with different types of slugs, i did not notice any particularly tight spots in the bore . At least not as noticeable as in some other barrels i have slugged .

It is good to hear from other SW 500 owners . I was wondering if my gun was an odd one with tight throats , or if it was
a common problem .
Also good to know that it solved your problems for you.

I was thinking about trying a few more loads in the gun, but i think that with a groove diameter that is close to .0025" larger than the throats , it is pretty much a waste of time .

thanks again

Joe