John,


As I think I've mentioned to you before I favour light chamber throat reaming and my reason for this is when I am unable to chamber a cartridge case with a bullet which is too large a diameter to allow it. This is seen principally in blackpowder era rifles where the factory specs were a little less than precise because they relied upon blackpowder to 'bump up' bullets to fit the bore. Almost all my blackpowder era rifles have been this way and without a bullet one to two to three thousandths of an inch overbore I have experienced terrible accuracy using smokeless powder, even very fast burning ones like Unique. Bullets have tumbled and have been all over the place. I shot out one chronograph machine because of this. Leading has been fierce because of bullet blow-by by hot gases. Every smokeless era rifle has been fine and the groove diameter has been close to standard bore size. These rifles in the 1905 period or thereabouts have never caused me a problem. With regard to the blackpowder rifles made prior to 1898 ( two .40-65's in models 1895 and a .44-40 and .38-40 both in models of 1889) I have elected to ream their chamber throats, by hand, with throating reamers provided by Pacific Die Co until dummy rounds, with my chosen bullet diameter seated, would just chamber with ease. There is a pilot supplied with each reamer and the reamer is screwed to a T handle. The stock must be removed to allow clearance to turn the T handle. I have had to make only one 360 degree turn in one of my .40-65's but the other rifles allowed the dummy cartridge to chamber much sooner and with a rotation of about 270 degrees. It's not important. Go slowly, bit by bit , constantly checking to see if the round will chamber. The reamer is so sharp you can feel it cutting. Not much pressure is required. You will 'feel' how much is required. Only turn the reamer in a clockwise direction or you will blunt the flutes. It is a precision instrument and should be frequently blown out with an air gun to remove shards of metal. My accuracy problems have been eliminated and so have the leading problems. The reamers are a little expensive but well worth it. I think they cost me about $ 80.00 U.S. each and the T handle was $ 25.00 U.S. The service was outstanding. I have no idea why other folk don't do this, even on high collector type rifles. There is no exterior evidence at all. I suppose a chamber cast might show it. I don't care. My rifles shoot really well now, but they sure didn't before.

 

Excellent write up Smithywess, Thanks! I especially appreciate your process description.

I’m trying to visualize and understand the execution as well as the surfaces being impacted.

I was most surprised by how little you had to rotate. I guess I had pictured it taking 10, 20 or even more turns. So you are only turning a very little bit, then testing with your dummy round. This also leads me to believe you don’t have need of a depth-stop, since you are going at it so slowly.

If this is a throat reamer, should I assume you use a bushing to keep the center of the reamer centered in the chamber.

You’ll see from my questions how new I am to the topic but that’s how a fellah learns.

One thing I’m seeing (or think I’m seeing) is that it’s not going to be the same in each case. Below are some throat slugs. The pair together are from a 45 Colt Cowboy. The other is a cerrosafe cast from a 375 (black magic marker on what I understand to be the throat – perhaps at 12degrees). The other is a pound slug or chamber slug from a black powder chamber of a 1906 32-40 (a rather poor one for detail due to the corrosion in the first three or four inches of that bore). It appears to me that in some cases, the 45Colt and the 32-40 you could be shaping the leade angle with the reamer, while in the case of the 375 you’d not be touching or altering the leade angle.

One thing I do know is that I know little enough that two things would have to be present before I’d tackle it: One being my making a chamber mold of one kind or another, and two), my having failed in the pursuit of the five or six other things we address to get a gun to shoot correctly (listed in my original question).

Again, I appreciate your taking the time to add to my understanding. I hope others jump in too.

 

I'm lucky in that my rifles have all responded to the cast bullets being fit to them, so I've never considered reaming the throats. On the other hand, after I reamed (lengthened) the forcing cone on my first shotgun, and saw what it did for lower pressures and denser patterns, I've done every one I've got, and several more for friends. Absolutely no down side to this on shotguns...so if nothing else is working for your rifle what can it hurt?

 

Sgtdog,

I agree with you that every alternative to obtaining accuracy should be tried first. Different powders, different cases and primers,hollow based bullets, etc etc. There comes a time however when it becomes obvious that the rifle either gets sold, hung on the wall or reamed. There is no bushing around the chamber body area itself but the pilot at the end ,which rotates, is sufficient to keep the reamer centred. The bore diameter across the lands on a slugged bullet must be relayed to the reamer manufacturer in order that he sends you one that is fitted to enter the leade. When I rotate the reamer I gradually apply pressure through the first 5 to 10 degrees of turn until I feel (and sometimes hear) it cutting. When I quit turning I also gradually relieve the pressure the whole aim being ,one would hope, that evenness results. I'm not making a benchrest rifle here to hit flies but rather one that will close up 8" to 12" groups with some misses to one and a half inches with head on hits and no leading. This is at 80 yards off a sandbag and that's better than 'minute of deer'. Even 300 grain bullets out of the .40-65's will do that, after reaming. Dave at Pacific Die didn't seem at all fazed when I asked him to cut reamers so there must be lots of folk doing the same thing I would think.

 

Again Smithy, I appreciate the dialogue.

I probably seem slow here but the reason I ask about Throating reamer vs a Full Neck+Body reamer is because from pictures I Google I'm assuming the throating reamer does not fill the chamber end, losing that automatic centering feature I can envision with a full bodied tool. I had not thought of the pilot’s ability to center.

Also, from a post I picked up in reading I’ve read the ‘centering’ mentioned as a precaution. Here is one where it is mentioned.

“I have a bushing that fits over the PT&G Uni throater to act as a rear alignment guide. This bushing is held in place by an action screw or scope base screw. The back end is faced off 90 degrees to the bolt race.

I use a Lambeth/Kiff Micrometer Adustable Reamer stop mounted to the Uni Reamer to set the cutting depth of the piloted throating reamer.

I can cut the throat without removing the barrel from the action or remove the barrel and put it in a barrel vice then cut the throat using the Micrometer Adjustable Reamer Stop and a Hand driver. This all can be done by the gunsmith without a lathe.

I have a customer seat a bullet to the desired seating depth and cut the chamber for the desired bullet seating depth either engaged or the jump.

Why don't you ask Dave Kiff about this also. I think he will say this is the second best way to custom throat a chamber.

Rustystud”. (taken off Benchrest.com – although I know our focus is not benchrest here I thought it of interest.

And another piece of info I keyed in on is one I’d like to learn more about. I sent a message on the PT&G web site but no response as yet. Ref: Spiral Flute « Daily Bulletin
Spiral-Fluted Throat Reamer
Some gunsmiths prefer to start chambers with zero freebore, and then cut the throat in a second step with a throating reamer. You can also use a throating reamer to extend the freebore as needed to shoot a longer type of bullet. PT&G offers an excellent throating reamer with spiral-cut flutes. We have received very positive feedback on this product from respected gunsmiths. One smith raved about the spiral-fluted reamer, saying it “cuts smoothly, with zero chatter, leaving a very fine throat finish”.

Regarding my two conditions... that's largely said in light of my ‘zero’ experience. I could imagine someone way more experienced who reamed simply due to preference or because they prefer to customize a chamber to a particular bullet preference.

Still hope other’s contribute. Wind, srf, and a good friend here locally “Green Lizzard” have added a lot to my understanding but I’m sure others’ experience and perspective would be valuable to more than just me. Thanks Again!!

RB Rider, appreciate your comments as well.

 

Well, while waiting for other contributions to help educate me I am going to toss another hat in the ring when it comes to throat modification. And this one might be considered heresy by some but it worked judging from the chamber cast before and after and from the shooting results after the solution was applied. It comes with permission from an MO member who has not posted pictures yet and who is a man of few words at the keyboard, but who was willing to let me post this.

First off the problem rifle and the solution belongs to Green Lizzard, (Bill) who owns a few reamers himself and who has not bought a bullet in about 30 years, meaning he doesn’t get stumped easily these days. Bill and I have talked throats and chambers and bores considerably and he has guided me through the process of chamber casts and obtaining a throat slug among other things and I always find what he has to say of interest.

The problem rifle:

Buffalo Bill Commemorative 30-30 -- several bullets, several reversals and several restarts down the road.


Final straw:
Finding leading once again with the latest properly sized bullet sample Bill went home and pushed the new subject bullet from the chamber, no cartridge, just bullet, and a push, not a blow. The throat shaved the neatest little shaving ever off the bullet. Leading had begun from the very first round although accuracy remained good since leading accrued only in the few inches near the throat. Bill enjoys paper patch too among other things. This one didn’t tolerate paper patch at all.

When I called after getting back from Idaho this latest trip I immediately decided to drive over to Bill’s after hearing of the fix applied to this problem child.

The fix:

I’ve often thought of lapping but this lapping is more of a pinpoint strike on the problem area, instead of the entire throat and bore. The cone and shaft used to lap by hand turning is from an old valve lapping guide that Bill shaped to an angle he thought presented the best tangent to the bullet ogive. The case is drilled to tightly accept the shaft for centering purposes.

Initially the lapping cone, when extracted after a few turns presented two distinct lines (refer to arrows) where the cone touched the near edge of the throat where lead was being shaved, and perhaps the high side of the leade ramp. As he turned the fabricated tool he watched these two lines begin to converge or grow closer to one another, eventually making for one wide line around the cone, indicating a smoothing and shallowing of the throat.

Outcome:
First time out after the exercise, accuracy remained good as before, but zero leading. Next time out, this time with past-failure bullet samples loaded, which also leaded, same result. Accuracy with no leading. He pushed these plain base a little faster, still no leading.

By ensuring the cone was sufficiently smaller than the chamber to keep lapping from occurring on the chamber walls he believes from inspection that he is only impacting that area of the throat that was shaving lead. I thought it was an interesting little project that may have been accomplished with firelapping but not without a considerable amount of fire-lapping.

A throat reamer would have been the conventional way to do the job too, but despite 30-30 being one of his favorite calibers, this being one of six he loads for, it is not a caliber for which he has a reamer.

Bill is an old Aircraft Machinest so perhaps an appropriate disclaimer for people like me might be: "Do not try this at home". I believe I just might try it at his house though should I have a problem that defied all other efforts.

 

bumping this morning. Seems like it falls off pretty fast. Still hoping to read our more experienced member's technique.

 

Ok... last bump to entice input one more time. I'm interested in technique if you're willing to share.

 

took it out again today problem child behaving nicely

 

Wish I coulda gone with you Green Lizzard! I'm so anxious to get that 32-20 back here and determine the scope of the problem. i'll know a little bit more about it by then if I get time with it. I'd really like to learn this reamer business but if I don't buy a PTG Uni-Throater then I'm gonna give your lapping tool a whirl. Either way you'll be doing some mentoring if you're up to it.

 

Well it’s back, the 32-20 that is, back in Oklahoma, and by next week I hope to be caught up with chores, etc.

I shot this rifle for acceptable accuracy after the John Taylor reline.

The problem is leading. With gas checks leading was bad enough for accuracy to fall off within 30-40 rounds. With plain base bullets leading is immediate as you’d imagine from the photo.

I’ve heard people say gas checks clean up behind a bullet. I’ve heard others strongly disagree. After looking at these bullets I wonder if both might not be true and whether they do or do not depends a bit on the cause of the leading. In other words, do they leave it behind, like a shaved lead ring, sort of unattached deposits, or do they smear it on the walls? I’d imagine this would leave significant amounts behind to be ironed on as you continue shooting. I could imagine gas checks helping for a while but not for long.

This bore slugs right at .312. I’ve tried both .313 and .314 sized bullets with different strategies, lubes, loads, etc.

When I queried Mr Taylor about the throat this is what he had to say: “My chamber reamer is to SAMMI specks and does not have a taper throat. It has seemed to work well in the many chambers I have used it on but it might be a good idea to run a throat reamer in to help. I have used this same reamer for about 15 years with no complaints but I have always thought it should have a taper throat. The 25-20 is set up the same way as well as several other old stile reamers.”

The photo: I recently took Green Lizzard’s queue and lightly tapped a few sample bullets into the bore (just like you might a bore slug) to get a clue as to what they are doing upon entry. I then tapped them back out from the muzzle. I don’t think this throat and these bullets will ever get along.

So, unless a throat reamer magically falls in my lap in the next couple days, I’m off to my buddy’s for a tutorial on improvised throat lapping.

 

Sgt Dog 0311,

Glad to hear you're still at it. I can't recall if you said what your bullet alloy is? Also what velocity are you driving these leading bullets? What is your lube. Are you sizing them or shooting them unsized ?

 

Hi There smithywess,

The alloy is about 2/3 WW with some softer lead mixed in, for about 12 bhn. I'm driving them at about 1200fps. My mold drops them big and I started out sizing the gas checked bullets I took over to Wind's this summer at .313. When I got back to the cabin I tried some PB sized at .314. Leading was severe. Next step was to quench the .314s and the PB came out at 17bhn. That helped the leading on the patches just a little but still impacted accuracy in two five shot groups. I have not quenched the gas checked bullets nor did I try sizing any of those at the .314. Lube has been of two varieties. Green Lizzard has a proven concoction I finger-lube with and the second concoction was Wind's Wonder Lube (pan application). Not sure if you can see from the photo with the lube in the way but the throat seems to be plowing lead, even between the leades. I could size them smaller (to bore size, and eliminate the plowing), but then my seal might not be as good. I hope to get a chamber slug (pound cast) this week or early next before I go further with any throat modifications.

 

hey sarge, your offhanded comment about sizing to bore size got me to thinking. maybe some of these guns dont like fat bullets. ithink bore size or plus .00005 over would be worth a try (make the bullet fit the gun vrs gun to bullet

 

I'd be interested in the result of this.

 

Im watching this thread closely, but I have to ask, what is "finger lubing" and how does it work? I figured it is applying bullet lube by hand? As a way of trying out lube before doing a full batch? Also on polishing the lead ( to knock off square shoulder ) are you using a cast lead bullet , or making a steel " bullet " and then using lapping compound? Thanks for all of your help,
BoB

 

kybob you can reduce alox (thicken it) by cooking down or brew up your own using a combo of bees wax alox and paste wax. then just roll it on. i think sarge has a video of me doing it. maybe he can post it. i have used this method for over 25 years, even gave away my lubesizer. its fast and easy but i know its not for everyone. the reason i started doing it that i was shooting a lot of as cast soft bullets and the lubesizer was upsetting the nose. it just got to be a habit

 

Green Lizzard, I'm thinking the same thing but have to admit, even if it works I like the idea of a tapered throat, especially in light of what Taylor says. Btw... he suggested the same thing. Now I have to get another sizer, unless you have something in that size.

smithy, I'll sure keep you up to date. You've been a big help so far.

kybob, Green Lizzard is the master at this. He can lube five or six bullets to my one. The short ones are the big challenge for me. I have a little video of him I did just for grins and giggles and if I can figure out how to post it I will. Might have to get some help from Wet Dog for that.

 

Well, it certainly does look like the intersection of the 32-20 25 degree angle leade with the bore and the grooves could stand to be eased a little.
I'll bet it won't take much though.
I'll be watching.....:flute:

 

john i have .311, .312, .314, .316 have a .308 on the way which i was planning to open up to .309 (may be here havnt talked to denny)

 

kybob pic on first page

 

Hey there John -- We've had this fat bullet discussion before. Historically folks made the bullet to fit the rifle. Few, if any, were fat ones. If you wanted more weight, you added length. It would appear to me you are using your rifle as a bullet sizing tool.

Lead is repositioned on a correctly sized/shaped bullet as it is fired and moves down the bore. Most of it leaves the barrel with the bullet. Your picture is showing me the affects of your rifle trying to size an incorrectly shaped bullet and leaving nowhere for all that extra lead to go - but to be left behind as a severely leaded barrel. I have tried to show this in a picture. Your bullet is is the one on the left...

View attachment 81379

Easing the throat may help, but I doubt it will correct the situation with the bullets you are trying to use. I have some "traditional" bullets I could send you, and you could compare the leading results, if you like.

Hope this helps. Best regards. Wind

 

wind an extreme example of this is an 1889 swiss infantry rifle i have. the bore is .298 groove is .307 std service ammo for this thing .316 dia. pater patched to .322 dia. now this whole mess was squirted through that tiny bore. it has a throat .650 long slowly tapering. now i dont know how it shot as ammo is rare but it couldnt have been too bad, it remained in service till 1896 or so

 

John, I tried to duplicate your World Record lead shaving examples, by shoving a bullet into my 38-55, and one into my 45-70.

I got nothing like your example......

With the 38-55, the bullet I used was only about .0005 inch larger than the groove diameter. There were no shavings visible on the bullet. There were two very fine slivers of lead on the first patch that I ran thru the bore afterwards. For reference, the leade angle on the 38-55 is 6 degrees.

With the 45-70, the bullet was about .0015 inch larger than the groove diameter. There was no shavings visible on the bullet, or on the first patch thru the bore afterward. For reference, the leade angle is 12.75 degrees. However, I have run some firelapping rounds thru this barrel, and I know that the entrance to the lands is a shallower angle than standard.

I'm about to head off for Thanksgiving dinner. I will take a photo of the bullets later.

How sure are you that your bullets are .002 over groove diameter?

Best Regards,
Steve

 

You know me Wind... Always leading with a blunt face. But if I do have to 'back this truck up' I'll appreciate the offer on the bullets and be contacting you.

Actually, I've been evolving away to some extent from my wide meplats infatuation, starting with the 32-40! The 38-55 will be a LFN and hope to double-down there with utility in the 375 as well, which WILL be a 'truck in reverse' (and you know that full story).

So, I think you have a valid point with this one which I am not ignoring, but I'm gonna worry over it some more with this bullet before giving up. If I don't get it to my satisfaction I will take you up on your offer. And even then, if they don't fly well at longer ranges then I'll be looking for a different mold when money is back in fashion here.

On a positive note I've had excellent luck with a couple of the large meplats in the bigger calibers. Good thing too, since the molds are enough of an investment that you can't afford too many instances of 'poor first choice'.

Steve, appreciate the input here too. I've got into the habit on the last couple rifles of shoving a sample bullet into the breach end and inspecting it closely before going further. So far this is the worst example of those I've tried. I am very confident on the sizes, both bore and bullets. And for this 32-20, a close inspection (for whatever the naked eye is worth in these cases) does make you suspect a very abrupt leade angle. I'm gonna try the .312 first and then we'll see what that looks like with the same exercise. If that produces shavings or still plows lead, then I'm gonna appeal to my buddy Green Lizzard for some help with lapping the angle. I really wanted to get a throat reamer, as much for the experience as anything, but its a choice between a reamer or a mold for the 38-55 just now, and I've watched GL work some magic so if he's game that will be step two. And like I said, I think maybe the answer could mean a little of both.

This bullet is for my 35REM. And has a more graceful ogive. If you can enlarge you can see the leade angle engraving peter out on the last driving band before the gas check. No shaving, no lead on patch and no lead fowling to alert me to a problem after shooting.

I sure value and appreciate the input here from everyone.

Bill, I'll give you a call tomorrow and see how your day is shaping up.

 

Here is the picture I referred to in my earlier post.
I think you can tell which is the 38-55, and which is the 45-70:biggrin:

Neither one was pushed in far enough to fully engage the rifling for the whole length. The back end of the bullets would have been roughly even with the front of the case.

 

great pictures you guys