It is hard to measure a slug that has been pushed through a bore with 5 lands and grooves.
model 25 colt throat??
- Thread starter toad67
- Start date
It is hard to measure a slug that has been pushed through a bore with 5 lands and grooves.
I had my 25-5 for a number of years before I heard of the oversize issue. It has a six inch barrel and is damned accurate with the .452 lead bullets. I did check the cylinder and the .452's dropped right through. I never told 25-5 about this and it is still damned accurate and a favorite pistol.
cowboy4evr
Member
Yes it has 5 lands and grooves . You will still get a fairly accurate measurement. It's being done all the time .
GCF
Member
5 lands / 5 groves. Tough to get an precise measurement off a slug - w/ a mic or caliper. I've heard that someone makes a special tool for the job, but I don't have one.
Anymore, for the purposes of determining optimum sized diameter for CB's, I have pretty much quit worrying about S&W revolver barrel groove diameter. From what I've seen, their .45 colt barrels are pretty uniform & as you point out, .452" CB's - through uniform .4525" throats, should provide good results.
Same goes for their .44, & .38 / .357 barrels, as well.
As far as the "oversize throat" M25-5's go, I am quite sure that with a little ingenuity (soft alloy maybe?), they can be made to shoot satisfyingly tight groups - right along w/ the rest of them...
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GCF
Member
Agreed - you can get a "fairly accurate" measurement. I've done it in the past, but never felt that the results were precise.
Frankly, I'm usually more concerned w/ non-uniform, and / or undersize cylinder throats, for cast bullets.
l shoot .455''/250gr soft swaged Remington bullets in my 10 1/2'' 460PC..
Loaded at 45LC velocities, stuffed into full length 460 Mag cases.. Very accurate too..
Putten a ''little squeeze'' on those Remingtons didn't hurt them at ALL
Loaded at 45LC velocities, stuffed into full length 460 Mag cases.. Very accurate too..
Putten a ''little squeeze'' on those Remingtons didn't hurt them at ALL
GCF
Member
Jaymoore - Thanks for the info. Always new there was a special tool for the job, & also, that there was a good reason why I didn't personally own one...
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Rumor has it, that "some" cast bullet manufacturers (Dardas for example) have these tools, & will measure bore slugs - as a customer service.
Slug cylinder throats and measure. No lands and grooves there.
Slug barrel. What kind of pressure does it take to presses that slug through throat. If it takes much pressure bore is bigger than throat. Bad. Throat needs opened up. If it fall through throat is bigger than bore groove dia. Not so good. Use throat size bullet or make a new cylinder.
You could always make a test plate. Drill series of holes in say 1/2 plate. Use and adjustable reamer to make one hole .451, another .452, .453, .454, .455 etc. Check slugs with that, but what you really want is throat size, so slug them and measure.
I have made my own cylinders because I can, but I think it is mostly a whole lot of hand wringing over nothing. If I just had one 45 colt (I have 5 and am going to build a couple more.) and it had over sized throats I would shoot what ever sized lead bullets fit the throats. Maybe coated bullets.
Slug barrel. What kind of pressure does it take to presses that slug through throat. If it takes much pressure bore is bigger than throat. Bad. Throat needs opened up. If it fall through throat is bigger than bore groove dia. Not so good. Use throat size bullet or make a new cylinder.
You could always make a test plate. Drill series of holes in say 1/2 plate. Use and adjustable reamer to make one hole .451, another .452, .453, .454, .455 etc. Check slugs with that, but what you really want is throat size, so slug them and measure.
I have made my own cylinders because I can, but I think it is mostly a whole lot of hand wringing over nothing. If I just had one 45 colt (I have 5 and am going to build a couple more.) and it had over sized throats I would shoot what ever sized lead bullets fit the throats. Maybe coated bullets.
I use the male part of bullet sizing dies to determine forcing cone/bullet
size for a particular gun. These dies are available from Lyman or RCBS.
First die that shows any resistance will be the perfect sizer for that guns' bullets
size for a particular gun. These dies are available from Lyman or RCBS.
First die that shows any resistance will be the perfect sizer for that guns' bullets
No argument from me! (See Post #10.) My usual measuring aid for throats is an expanding ball gage. Good for detecting taper and front edge constriction. A dial bore gage works, too, but is probably more sensitive than is really needed.
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cowboy4evr
Member
Well , to say that the throat size is what you really want ? I have to disagree with that statement . If you remember correctly , several yrs ago Ruger in 45 Colt had cylinder throat sizes that were undersize , around .448-.450 compared to the " groove " diameter of the barrel . So you would end up a gun with mediocre accuracy and a fairly well leaded barrel after a session at the range . You had to ream out the cylinder throats to at least .4525 , providing the groove diameter of the barrel did not exceed that measurement .
You need " both " measurements to get the correct cast bullet size . The cylinder throats have to be at least the same as the groove diameter of the barrel . It's a balancing act , for one without the other is wasted time and money .
Several yrs ago I bought a brand new S&W 25-10 . It had horrible accuracy and it really leaded up the barrel shooting cast bullets sized .452 . I slugged the barrel , again and again and always got the same measurement , .453 . It also had a real tight spot where the barrel threaded onto the frame when I pushed a lead slug all the way down the barrel . The new measurement was .448 . It took several hundred rounds of " fire lap ' bullets to remove the tight spot . I had to cast bullets .454 and ream out the cylinder throats to match the barrel . Then it settled down and performed well . Revolvers made today are not set up for shooting cast bullets . They are for shooting plated / jacketed stuff . If you want to shoot cast with accuracy and not much leading of the barrel it takes some time and effort to achieve those goals . Like I have said before , go to LBT Molds and buy Veral Smith's book , " Jacketed Performance with Cast Bullets " for about $15 or so . It explains the process in detail and is well worth the cost . Veral is considered a well recognized expert on shooting cast bullets in revolvers , semi auto's and yes , even rifles . Regards , Paul
You need " both " measurements to get the correct cast bullet size . The cylinder throats have to be at least the same as the groove diameter of the barrel . It's a balancing act , for one without the other is wasted time and money .
Several yrs ago I bought a brand new S&W 25-10 . It had horrible accuracy and it really leaded up the barrel shooting cast bullets sized .452 . I slugged the barrel , again and again and always got the same measurement , .453 . It also had a real tight spot where the barrel threaded onto the frame when I pushed a lead slug all the way down the barrel . The new measurement was .448 . It took several hundred rounds of " fire lap ' bullets to remove the tight spot . I had to cast bullets .454 and ream out the cylinder throats to match the barrel . Then it settled down and performed well . Revolvers made today are not set up for shooting cast bullets . They are for shooting plated / jacketed stuff . If you want to shoot cast with accuracy and not much leading of the barrel it takes some time and effort to achieve those goals . Like I have said before , go to LBT Molds and buy Veral Smith's book , " Jacketed Performance with Cast Bullets " for about $15 or so . It explains the process in detail and is well worth the cost . Veral is considered a well recognized expert on shooting cast bullets in revolvers , semi auto's and yes , even rifles . Regards , Paul
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GCF
Member
The assumption of the "throat size is what you really want" camp, is that tight spots (choke points) aside, the bore diameters are normally correct, but the throat ID's are normally under size - & non-uniform.
Sounds like the frame thread choke point - on the M25 described, was a bigger problem then the actual bore diameter. Removing it (several hundred fire lapping rounds is a lotta' work!), - & correcting the throat ID's, allowed you to achieve cast bullet nirvana, aka "balance".
As a side note, I was speaking w/ Alan Harton of Single Action Service (Houston, TX) a while back, when the subject of frame thread choke points came up. Although I don't recall all the details, he indicated that there is a viable alternative to lapping them out. Although I could well be off base, it seems like he was talking about "adjusting" the barrel thread size - w/ a slightly under size die. That, or a slightly over size tap - in the frame.
Does that sound reasonable? Again, it was 5 - 6 years ago, he didn't really go into detail, & my memory ain't what it used to be.
BTW, great suggestion about Veral Smith's book. That man doesn't get 10% of the credit he deserves...
cowboy4evr
Member
I remember reading an article several yrs ago . One of the famous gun writers had received 2 ruger 45 colts , one blackhawk and the other a vaquero . He had problems like I expressed in my previous post . The one ruger he fire lapped the barrel , the other he had the " Taylor throat " cuting done , literally removing about 1/2" of rifling and correcting the diameter of the barrel where it threaded onto the frame . I have never had the Taylor method used . I simply fire lap if necessary . Not only does fire lapping remove the tight spot at the junction point , but it also removes machine marks in the barrel and ultimately puts a nice slow taper in the barrel . I do 12 at a time , shoot 2 , then run a bore snake down the barrel to clean it , shoot 2 more etc . It is time consuming , but I have more time than money . Regards , Paul
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xuout1
Member
There is no way a old black powder 45lc revolver is going to punch through a animal the size of a elk and kill a Indian behind it. What are we talking about a bullet traveling at maybe 500 fps at that range with black powder loads ? Even a 30/06 has a hard time going through a elk at that range if it hits bone. But i could be wrong or miss read this statement.
Dale53
Member
The U.S. Army standard was to shoot through a horse at 100 yards. It did NOT include killing the "Indian" hanging off the side. The idea was just to put an enemy afoot, out West. They were no longer much of a threat and in many areas out West, being afoot was nearly a death sentence.
After watching the penetration on a deer facing me at ranges up to 85 yards (full length penetration) several times with a good handgun, I believe it. Elmer Keith mentioned in his writings, that penetration of a good handgun with a lead solid would far exceed a good rifle with expanding bullets. Elmer had considerable experience on game with both rifle and handgun, and again, I believe what he stated.
FWIW,
Dale53
After watching the penetration on a deer facing me at ranges up to 85 yards (full length penetration) several times with a good handgun, I believe it. Elmer Keith mentioned in his writings, that penetration of a good handgun with a lead solid would far exceed a good rifle with expanding bullets. Elmer had considerable experience on game with both rifle and handgun, and again, I believe what he stated.
FWIW,
Dale53
xuout1
Member
A 150 pound deer is a whole different animal then a 900 pound horse. And you are definitely correct that the hard cast bullets will penitrate extremely well. But the velocity out of a black powder 45lc in a pistol at 100 yards is probably going to stop in the first layer of muscle. Now out of a black powder rifle it probably would diable a hores.
I wouldn't be so sure that a black powder 45 colt would only be going 500fps and stop in the first layer of muscle.
A 45 colt case holds 35gr of FFFg black powder and using a 250gr bullet it gets 900fps from a 7 1/2 barrel (older colt). Not much differnt than todays factory loads. It would loose about 125fps in the first 100 yds. So about 775 at 100yds. 775x775x250/450240=333ftlb. About the same as a modern 158 gr 357 at 150 yds. or a snub nosed 38 special at the muzzle.
A 45 colt case holds 35gr of FFFg black powder and using a 250gr bullet it gets 900fps from a 7 1/2 barrel (older colt). Not much differnt than todays factory loads. It would loose about 125fps in the first 100 yds. So about 775 at 100yds. 775x775x250/450240=333ftlb. About the same as a modern 158 gr 357 at 150 yds. or a snub nosed 38 special at the muzzle.
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No disrespect intended, but you've obviously never shot any factory original black powder 45 Colt ammo.
My brother owned a fantastic 25-5 with 8 & 3/8" barrel. This was a LSI non-pinned model. We ran a box of original Dominion 45 Colt black powder ammo through it. This stuff had the old 1909 wide rim for use in DA revolvers like the Colt New Service. That stuff was really hot by 45 Colt standards, with a 255 gr hollow base lead bullet going over 900 FPS. It was also surprisingly clean burning. No problem with clean up once we got home.
Incidentally, my brother and I both used that revolver successfully for IHMSA silhouette out to 200 meters. No problems hitting or knocking down rams.
Best Regards,
Jim
