Close up of 625-8 JM EDM rifling

[1-1917]

Does anyone know if S&W is still using this kind of rifling? I have accuracy problems with this revolver and I wonder if the EDM rifling is a contributor to the accuracy issues.

The edges of the rifling are just shallow ramps. I can't figure how this is able to grab a bullet, especially a cast one.

Anyone else have accuracy issues with a 625-8? I'm wondering if some of these have cut rifling? It seems they either shoot really well or really bad. Mine has been on the real bad side. Trip to S&W helped but still lacking in the accuracy department.

 

[amazingflapjack]

Will have to look at the rifling in mine, but it is very accurate.

 

[birdshooter]

Mine leads terribly with cast bullets. Every other Smith I have shoots them great.

 

[Dale53]

I shoot NOTHING but home cast bullets in my 4" JM Special. My bullets are cast from my "standard" bullet alloy - WW's+2% tin. My bullets are sized at .452" and my cylinder throats are about .4525". I can actually feel the bullet entering the cylinder throats. I have checked a couple of my buddie's 625-8's and they are just like mine.

My gun will regularly shoot under an 1" off a rest at 25 yards. My most used bullet is the Mihec "true copy" of the H&G #68 flat based bullet. I mostly shoot target loads (4.0 grs. of Bullseye or equivalent) but have also driven that bullet to 1000 fps. with excellent results.

I forgot to mention - absolutely NO leading. I seldom clean the bore.

FWIW
Dale53

P.S. I also have a Smith Model 520 (4" "L" frame with EDM barrel in .38/.357). It also works beautifully and shoots like a house afire! NO leading, NONE... rdm

 

[Frank46]

Looks like the cut around the rifling at the muzzle isn't concentric. Lower part about 5 O'Clock looks shallower that what you can see near 12 O'clock.May need the crown and muzzle recut. or it just might be the way you held the revolver when you took the pic. Frank

 

[BLUEDOT37]

Is your picture above of a 625-8JM's muzzle?

As far as I'm aware the 625-8JM is a (5) groove barrel & is EDM/ECM rifled, the same as the 25-13, 325TR, & 325NGs I have. Your picture shows (6) grooves?

I have a 625-8PC & S&W says it has the broached rifling. It does have a (6) grooved rifling. They also call it "deep cut" but my measurements show there's no meaningful difference, that I can measure, from the others.

They all have grooves that run .0042" to .0047" deep. 45's are not noted for having deep grooves.

Very few of my S&W have done well with cast lead bullets & I converted to using only plated or jacketed bullets in them some time ago, to avoid that grief, and they are very accurate with either. I prefer .452" plated but .451" does fine too. Throats run .452".

I don't know what problem(s) your's might have, or what S&W did to try & correct your accuracy complaint, but mine have had a few things that needed addressing.

My 625PC had a barrel constriction, at the frame, right out of the box. A .443" pin gage, the largest that can be inserted into the muzzle, would fall smoothly thru the barrel until it got to where the barrel threads into the frame & would firmly be stopped there.

A .442" pin gage would pass the constriction. When firing coated cast lead bullets in it they started leading at that point. I hand lapped the constriction out but while the leading was reduced it was still generalized.

It might be worth checking to see if you have a barrel constriction.

The way S&W finishes the crown on virtually all their revolvers is largely disappointing to me. The rifling often has very poor presentation at the crown. Aesthetically not pleasing & potentially it can diminish grouping. I usually re-chamfer those.

Just a couple thoughts.

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625PC, before chamfering
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625PC, after chamfering, before polishing
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627PC, before chamfering
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627PC, after chamfering, before polishing
.

.

 

[scooter123]

Did this

With this

BTW, that is a model 620, a sort of variant of the 686 Plus with a 2 piece Tensioned Barrel assembly that also features EDM rifling of the same profile as your 625. I will also note that when I got home after this session with my 620 I found the rear mount for the scope had "shot loose". The first 4 shots were that grouping on the left (7/8 inch span) and I believe the scope getting loose was the cause for the two fliers to the right. As for the 3rd flier well to the right that was on me due to my jerking the trigger. I will also note that it took me 6 weeks of practicing twice a week to hone my skills to the point where I could shoot this well.

IMO my 620 is probably the equal in accuracy to my Dan Wesson 15-2, which means in the right hands (not me) is capable of sub 1 MOA accuracy.

Final Note; I got it into my head at one point that I should try some Lead ammunition in my 620 instead of always shooting jacketed ammo. The easiest way to do this for me was to simply pick up a box of Blazer Brass that featured lead bullets. That turned out to be a HUGE mistake that took me nearly 12 hours of scrubbing to get the leading out of the barrel. As a result I will NEVER EVER use bare lead bullets in any of my ECM rifled S&W barrels. In fact the only bare lead bullets that I current have in stock are Berry's 158 grain RNFP's Hard Cast to use in my 1892 for Cowboy Steel Shoots at a local range.

 

[shocker]

As a result I will NEVER EVER use bare lead bullets in any of my ECM rifled S&W barrels.

I shoot Penn Bullets' bare cast from Smith's ECM barrels. Four different guns. I suppose it's how scrupulous one defines clean, but a few strokes of a nylon or brass brush dipped in Ballistol makes the barrels clean enough for me.

 

[1-1917]

I shoot NOTHING but home cast bullets in my 4" JM Special. My bullets are cast from my "standard" bullet alloy - WW's+2% tin. My bullets are sized at .452" and my cylinder throats are about .4525". I can actually feel the bullet entering the cylinder throats. I have checked a couple of my buddie's 625-8's and they are just like mine.

My gun will regularly shoot under an 1" off a rest at 25 yards. My most used bullet is the Mihec "true copy" of the H&G #68 flat based bullet. I mostly shoot target loads (4.0 grs. of Bullseye or equivalent) but have also driven that bullet to 1000 fps. with excellent results.

I forgot to mention - absolutely NO leading. I seldom clean the bore.

FWIW
Dale53

P.S. I also have a Smith Model 520 (4" "L" frame with EDM barrel in .38/.357). It also works beautifully and shoots like a house afire! NO leading, NONE... rdm

Dale could you possibly take an eye loop or similar and check the rifling at the muzzle of your revolver? You obviously have one of the "good" JM models and I have one of the bad ones. I wish we could put them side by side and shoot them side by side with the same ammo and eyes.. You shoot a LOT of lead without an issue, I shoot 100 rounds and can't find the rifling. Similar alloys I suspect, similar bullets but such totally different results. There has to be something very different in these same model of guns. There are a lot more people than just me that have serious issues with these revolvers and another population that thinks they are they greatest thing since sliced bread. I see almost no middle of the road reports. What to heck is going on?

 

[1-1917]

Bluedot it is indeed an EDM 628-8 JM muzzle in the picture. It would be very interesting if there are both 5 and 6 groove 625-JM barrels out there. Anyone else care to check their 625s to see if the 5 or 6 groove? I'd have guessed that all 45s would be 6 and 38s would be 5.

 

[Tom S.]

Dale could you possibly take an eye loop or similar and check the rifling at the muzzle of your revolver? You obviously have one of the "good" JM models and I have one of the bad ones. I wish we could put them side by side and shoot them side by side with the same ammo and eyes.. You shoot a LOT of lead without an issue, I shoot 100 rounds and can't find the rifling. Similar alloys I suspect, similar bullets but such totally different results. There has to be something very different in these same model of guns. There are a lot more people than just me that have serious issues with these revolvers and another population that thinks they are they greatest thing since sliced bread. I see almost no middle of the road reports. What to heck is going on?

What you haven't said is whether you are shooting your own loads or some bought over the counter. There are some tricks when loading lead bullets. Soft lead requires low velocity and lube while hard lead requires more powerful loads to prevent gas escaping past the bullet and melting the lead as it does. That's a but of an over simplification, but it's fact. Have you tried coated bullets?

 

[jcelect]

Powder?

Have any of you folks that are having "leading" problems given any thought to the powder you are using? The major cause of leading is from the back end of a lead bullet melting from the hot gases of the powder ignition and being deposited on the bore. Pure lead melts around 600degs F! Harder lead(alloyed) melts higher. Less powder(slower bullet) or a cooler burning powder(slower burning rate) will reduce leading! I shoot a lot of lead in many calibers and found the "new" powder coated lead reduces leading! This powder coating is also an excellent lube! I have resized .357 bullets to .355 and found all that happens to the coating is it gets polished! IMHO, a good rule is to not shoot lead(without a gas check) over 1000fps!
jcelect

 

[Warren Sear]

...Final Note; I got it into my head at one point that I should try some Lead ammunition in my 620 instead of always shooting jacketed ammo. The easiest way to do this for me was to simply pick up a box of Blazer Brass that featured lead bullets. That turned out to be a HUGE mistake that took me nearly 12 hours of scrubbing to get the leading out of the barrel. As a result I will NEVER EVER use bare lead bullets in any of my ECM rifled S&W barrels. In fact the only bare lead bullets that I current have in stock are Berry's 158 grain RNFP's Hard Cast to use in my 1892 for Cowboy Steel Shoots at a local range.

That job would have taken about 3 minutes if you had used Chore Boy strands wrapped around an old bore brush.

No scrubbing need ever be required due to a leaded barrel.

 

[Sol-Invictus]

I have seen all manner of nasty, uneven, tool marked rifling in some of my most accurate guns and some pretty crooked forcing cones. If it shoots it gets left alone. Shoot it and see what happens.

Sent from my SM-T520 using Tapatalk

 

[Alk8944]

Unfortunately shooting cast bullets is not as simple as buying some off the internet and loading instead of jacketed bullets! There are three considerations when shooting cast bullets, barrel fit, hardness and lubrication.


The reason nearly everyone has problems with accuracy and leading is they buy commercial bullets without consideration of these requirements. Most commercial cast bullets, not swaged like Hornady or Speer, are too hard, too small, and do not have a proper lubricant for shooting!


Revolver cast bullets should not exceed a Brinnell hardness of 12-15, even for magnums! Anything harder will not properly slug up to fill the bore. Most commercial bullets are 18 Brinnell or harder because people don't know any better!


Cast bullets should be no smaller than .001-.002" larger than cylinder throat diameter, and this assumes the throats are at lease as large as barrel groove diameter. Drive a soft lead slug through your barrel and then try it in the cylinder throats. If it will not pass through the throats with little or no pressure the gun will never shoot cast bullets well. They will be inaccurate and lead the bore badly, sound familiar?


Most "lubricants", and I use the term extremely loosely, used on commercial cast bullets are chosen for shipping characteristics, not lubricating qualities. The absolute best cast bullet lube is Saeco Green. A lot will argue this point, they haven't used it!!!! No commercial caster uses this lube.


You have to do it right or don't do it at all. If you do it right you can shoot full power magnum revolvers and even rifles with plain based bullets and get little or no leading, even at 2000 FPS plus. The popularly quoted limit of 1000 FPS, or even 850-900, for leading means nothing if the above qualifications are met. And it makes no difference the style of rifling in the barrel!

 

[Warren Sear]

^^^ That right there.

I use my own bullet lube made from the same recipe as Saeco Green, which is the best there is IMHO. Use 1 pound of beeswax, 1/2 pound of Vaseline and a few ounces of STP oil treatment. You can throw in a couple of crayons for color if you want, but I don't bother with that.

I melt the beeswax, Vaseline, and STP in an old (but cleaned) metal paint can placed in a sauce pan partially filled with water. Test a small sample in cold water to see if it has the desired consistency. If too hard, add more STP until the lube is as soft as you want it.

After making a batch, I let the lube harden in the paint can. When I want to add it to my lube/sizer, I just melt the lube by again heating the can in a sauce pan partially filled with water, and then pour the melted lube into the lube/sizer.

This lube works well in all magnum revolvers (including full power magnums) with virtually NO leading.

 

[amazingflapjack]

Mine is all hand load LSWC over Unique.

 

[scooter123]

I shoot Penn Bullets' bare cast from Smith's ECM barrels. Four different guns. I suppose it's how scrupulous one defines clean, but a few strokes of a nylon or brass brush dipped in Ballistol makes the barrels clean enough for me.

Ever patch a barrel with ome solvent to let it soak for a bit and find that patch shredded with just one pass. I have and it was not the least bit enjoyable to clean up that mess. BTW, this during my pre Ballistol days and I would bet that Ballistol would have cut the cleaning time, perhaps even down to 6 hours. However that was the worst leading I have ever seen and have no wish to ever try that ammunition again. BTW, I suspect the true cause was a combination of a soft lead bullet and the ECM rifling and at some point I may try out those Barry's hard cast I have on hand.

 

[Mike SC Hunter]

I make my own lube out commode seals and canning wax. Sometimes I'll add a crayon or 2 for color. With my cast bullets I get little to no leading from calibers 32 to 45.

 

[dogdoc]

I tumble lube my commercial cast bullets with lee liquid Alox and no problems. Also must keep Bevel based bullet velocity low most of the time to prevent leading. I shot some coated acme 240 swc 44s yesterday at about 1000 FPS and they leaded my older 629. I may tumble lube those as well next time. The bullets with bevel bases that are too hard to obturate will lead every time unless velocity is low as in 900 FPS or less. My home cast flat based bullets that are Bhn about 12 hardly lead at all at higher velocity. I lube them with 50/50 Alox beeswax.


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