FlatTop 45 Colt Cylinder back from DougGuy

[FlatTop45LC]

I received my 45 Colt cylinder back from DougGuy yesterday and went shooting this evening.

I shot my normal load of Missouri Bullet Co 255 SWC over 9 grains of Unique in Starline cases. I shot 4 5 shot groups and ran out of light.

All groups were between 2 and 3 inches at 25 yards sitting on the ground with my elbows on my knees. That is what they ran before his work, but I had absolutely no lead build up on the cylinder throats or leading edge of the forcing cone.

I do have a bit of leading in the thread area of the barrel and think I have some thread choke. I am currently buying 18 bhn boolits, but intend to try 12 bhn next order.

[DougGuy]

Firelapping time maybe? Have you tried checking the barrel for thread choke? An easy way to look for it is to clean the bore real good, take the cylinder out and put a piece of white paper where the firing pin is, shine a bright light on it and look down the bore from the muzzle. Where the frame and barrel meet, you can sometimes see a ring in the barrel, where it distorts the light. I have seen these before.

The other way I like to check is basically feeling exactly what the boolit will feel going through the bore, I use a plastic jag and patch it really tight in the bore, push it down the bore a time or two, and if you have thread choke, when you get to the area that threads into the frame, the jag will get harder to push. This is the choke you are feeling. Some of them are so severe, the jag stops completely and you have to dang near destroy the cleaning rod to push it the rest of the way through. These are IMO, too restricted to firelap, they either need to go back to Ruger, because they are definitely below SAAMI spec and -could- pose a safety hazard because the choke is actually an obstruction in the barrel, which can cause pressures to rise unpredictably. The only other "fix" for this bad of a choke, is to Taylor throat the barrel, which mechanically reams the choke out much like a long extended forcing cone. It works, and works good.

If the jag only gets moderately harder to push, this can likely be firelapped out. Now that you have .4525" cylinder throats, the lapping boolits won't get sized down and they will work much better. If there is no visible distortion, and the jag does not change the amount of force required to push it through the barrel, there is NO thread choke.

I never had as clean of a barrel with my Rugers since I started using softer alloys and Felix lube. I think the Ruger rifling and alloy I can scratch with a thumbnail are a good match.

[FlatTop45LC]

I did a little test like that Doug. I patched a jag and pushed it through the barrel and it was smooth all the way through. I used a brass rod and brass jag.

I really think the bullets are too hard right now.

[newton]

Leading in that area is a real good sign of frame choke. Most noticeable when you slug a barrel, not so much with a jag.

I fire lapped mine out, was leading just like you say yours is. I know it was constriction because after lapping I could shoot the same boolits as before without it leading.

[FlatTop45LC]

Leading in that area is a real good sign of frame choke. Most noticeable when you slug a barrel, not so much with a jag.

I fire lapped mine out, was leading just like you say yours is. I know it was constriction because after lapping I could shoot the same boolits as before without it leading.

Maybe I need to look into fire lapping. I have never done it.

Is ther a kit I can buy?

[newton]

Look up the thread I did a few years ago and you'll see my process. I think there are still pictures too.

[newton]

Maybe I need to look into fire lapping. I have never done it.

Is ther a kit I can buy?

Yes, I think some sell it. I just cast a couple dozen boolits with the softest lead I had. Get two flat pieces of thick steel and a little thing of deremel compound. It's redish brown. Rub it into the boolits between the steel plates then load with the absolutely lightest charge to just get them out the barrel. I would have to go back and look it up, but I could see them come out the barrel and hit the target.

Mine was significant. So it took a lot.

[FlatTop45LC]

Thanks.

I will read up on it.

I am going to get some 12 bhn boolits to use anyway so I will fire lap with those.

[DougGuy]

I did a little test like that Doug. I patched a jag and pushed it through the barrel and it was smooth all the way through. I used a brass rod and brass jag.

I really think the bullets are too hard right now.

IF you can push a jag through it and the effort to keep it moving is constant and doesn't change, there is NO thread choke! Even a .0005" choke will make a noticeable difference on pushing the jag through the barrel. I just did one today, couldn't see any distortion, ran the jag down the bore 2-3x feeling for it, there was none! Used the brass pilot from the forcing cone cutter kit dropped it in the muzzle, it went smoothly all the way through the barrel with no noticeable change from one end to the other.

Still, sometimes firelapping will help groups for no reasonable explanation. Beartooth Bullets sells a kit for doing this, there are videos around that show how it's done.

https://beartoothbullets.com/bullets...pping_kits.htm

Personally, I have much better luck with 50/50+2% alloy and soft lube. Felix is the best that I have used, there are threads here on making it. I also got away from the Keith type boolits and have better luck with the large meplat round nose flat point boolits where the ojive comes from the meplat and transitions smoothly into the straight sides of the boolit, instead of having that shoulder like the Keith boolits have.

[newton]

With respect Doug, it might not be as noticeable to some as it is you with a jag. With a jag, the cloth can conform much easier, but with a lead slug it is easier to feel the tight spots because the lead does not give without significant pressure.

I thought a lot about this back when I had the problem. Lead right at the threads is indicative of the boolit being squeezed down for a brief second after it had already sealed itself in the throat. If it was boolit fit or hardness it would be also seen in other parts of the gun, cone and other parts of the barrel. If it was lube, you would see lead down the rest of the barrel in spots.

One day I'll make an animation of it. I can see it in my mind, but it's hard to explain in words.

[jwp475]

I received my 45 Colt cylinder back from DougGuy yesterday and went shooting this evening.

I shot my normal load of Missouri Bullet Co 255 SWC over 9 grains of Unique in Starline cases. I shot 4 5 shot groups and ran out of light.

All groups were between 2 and 3 inches at 25 yards sitting on the ground with my elbows on my knees. That is what they ran before his work, but I had absolutely no lead build up on the cylinder throats or leading edge of the forcing cone.

I do have a bit of leading in the thread area of the barrel and think I have some thread choke. I am currently buying 18 bhn boolits, but intend to try 12 bhn next order.

Try a harder bullet that is as larger or larger than your bore, always works for me.

[1bluehorse]

An easy way to find thread choke is with pin gauges...if one will start in the end of the bore it should go all the way through...if it doesn't try the next smaller one and so on until one will go through...subtract the difference and you have the amount of "choke in the bore....if I remember correctly in my Rugers with .451 bores the .447 was the one that would start...but that may vary gun to gun....but mine were all pretty close...

[newton]

An easy way to find thread choke is with pin gauges...if one will start in the end of the bore it should go all the way through...if it doesn't try the next smaller one and so on until one will go through...subtract the difference and you have the amount of "choke in the bore....if I remember correctly in my Rugers with .451 bores the .447 was the one that would start...but that may vary gun to gun....but mine were all pretty close...

I would say this is not only the easy way, but most precise way. It will show things that a slugging the barrel will not.

[FlatTop45LC]

Well I need to get a set of pin gauges! That sounds dummy proof for starters.

[DougGuy]

The only problem with using pin gages down the bore, is many barrels are distorted behind the roll marked warning on the outside of the barrel. You can often see shiny spots in the grooves behind the roll marks where the boolits have been wearing the high spots down. A pin gage won't normally go past this section and therefore won't go far enough to measure choke. We need an affordable source of 1" long gages that can be used in the frame window. I should contact Meyer Gage and see if they would make a run of 1" long gages that I can buy and then offer for resale here on the forum.

When I am faced with a problem like this, I often use the pilots from my .45 ACP throating reamer, they are about the same thing as a short pin gage, precision ground with sizes laser etched in them. They ride on the rifling lands.

[Nueces]

Another reason to consider a lathe to be an essential household furnishing.

[1bluehorse]

Dougguy, you are correct about the "high spots" that can be found under the roll marks also under dove tails etc; but the pin gauges will show those as well, as I said you just go to the next smaller size gauge and see how far it goes, if all the way then you know theres no constriction at the barrel frame only under the "writing"....if not then the next smaller until one goes all the way through.... then you know the depth of constriction at both (or more) spots.....careful firelapping will remove them all anyway....Marshall's (Beartooth Bullets) kit is an excellent system and easy to use....I bought a set of pin gauges years ago mainly to use for exactly these reasons, also to check cylinders....unfortunatley still have to "slug" for actual bore size though....

[jonp]

I bought a firelapping kit from Brownells or Numrich a while ago. Not sure which but pretty sure it was Brownells. You might try them. I was thinking of doing it for both of my Kahrs

[FlatTop45LC]

I am going with Beartooth.

I am going to order their 265 grain WFNGC and 255 grain WFN PB to shoot as a baseline and then lap and reshoot.

[DougGuy]

I bought a firelapping kit from Brownells or Numrich a while ago. Not sure which but pretty sure it was Brownells. You might try them. I was thinking of doing it for both of my Kahrs

Kahr barrels are made by Walther, they are match grade specs all the way, and they are freakin' beautiful barrels. Why would you want to firelap a Kahr barrel? If you want it to chamber and fire .452" boolits send me the barrels and I will throat them but I cannot see what firelapping such a pristine barrel will accomplish.