Can some of you experienced chamber casters help a fella out. I’m no dummy, but damn I can’t figure this out. Cast the chamber on my 45-70 today, and I can’t figure out how to read the SAMMI drawing to see how my chamber measures up to spec. Will someone explain this to me please? Here’s what I have.
Chamber cast?
- Thread starter STIHL
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RBHarter
West Central AR
If I'm reading your notes correctly I'd venture it had a lot of Hornady short cases and it's a slop rifled barrel under dia for rifle and fat for pistol .
2.1 is what the called case length is so that's ok the 2.066 step probably shouldn't be there .
The .455 groove is tight but worn tools in the case of broach or button rifling account for that .
The .484 neck seems a little tight but a Colts Ruger is cut that big for a .454 to plunk . My bet is that step at 2.066 will come out and get you up to a more comfortable .486 . You might not need it being able to shoot a .457 bullet .
I used to have "KISS" over the bench to remind me that cleaning is cheap compared to parts , and 86% of all mechanical difficulties are due to dirt , crud , and lubrication . The other 14% are are spread across catastrophic defect failure , age/wear/temperature excursion , honest mistakes , and stupid . In no particular order or percentage .
Crud looks like and answer here along with tolerant QC "standards" .
2.1 is what the called case length is so that's ok the 2.066 step probably shouldn't be there .
The .455 groove is tight but worn tools in the case of broach or button rifling account for that .
The .484 neck seems a little tight but a Colts Ruger is cut that big for a .454 to plunk . My bet is that step at 2.066 will come out and get you up to a more comfortable .486 . You might not need it being able to shoot a .457 bullet .
I used to have "KISS" over the bench to remind me that cleaning is cheap compared to parts , and 86% of all mechanical difficulties are due to dirt , crud , and lubrication . The other 14% are are spread across catastrophic defect failure , age/wear/temperature excursion , honest mistakes , and stupid . In no particular order or percentage .
Crud looks like and answer here along with tolerant QC "standards" .
@RBHarter my drawing skills are horrible. The 2.066 is where the leade tapers into the throat the 2.118 is the beginning of the rifling. Am I describing that correctly? The groove diameter mics .4557 .0003 shy of spec for groove so I figure as you worn button or rolling when rifling was cut. I just can’t decipher how far I’m supposed to be from the face of the barrel to the beginning of the rifling. I know I’m probably not making any sense here. The rifle chamber was clean. This rifle won’t shoot consistently it will shoot groups after it warms up but the cold shot will go 8-10 inches high and it’s possible to sling one here and there. Last ditch effort to feed it a steady diet of cast loads. It is an HR buffalo classic too, if that helps any.
Trying to decipher what diameter to size my boolits too.
Trying to decipher what diameter to size my boolits too.
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Ian
Notorious member
I think you forgot to measure from the breech face. If you were to make a pound cast using a lead-filled cartridge case this would be much easier to measure. However, kind of irrelevant except for making sure you're good to go on max trim length.
What I'd do is get an accurate measurement of case wall thickness just behind the mouth, double that, add .002", and subtract from chamber diameter just behind the leade. That number will be your maximum safe bullet diameter. Try that first.
What I'd do is get an accurate measurement of case wall thickness just behind the mouth, double that, add .002", and subtract from chamber diameter just behind the leade. That number will be your maximum safe bullet diameter. Try that first.
RBHarter
West Central AR
I wouldn't sweat the long throat . Too many of the modern production rifles have a chamber with a 45° step into the lands .
Basically you fill a sized case with hard lead or your cerosafe down about .1 to .2 then fit a dead soft , in this case about .450 slug for a bullet and chamber it using a 3/8 brass rod down the barrel give it a couple whacks to swell it into the throat , leade , and grooves , eject normally and measure the perfect form of your chamber .
I've not done one this way but I do have a couple I want to do .
Basically you fill a sized case with hard lead or your cerosafe down about .1 to .2 then fit a dead soft , in this case about .450 slug for a bullet and chamber it using a 3/8 brass rod down the barrel give it a couple whacks to swell it into the throat , leade , and grooves , eject normally and measure the perfect form of your chamber .
I've not done one this way but I do have a couple I want to do .
Well I was thinking it was something on those lines. So that makes sense. I may give it a try but I think I’m going to go with Ian’s suggestion and see what the brass thickness and throat diameter say and see what it come out too. That may give me a good place to start anyway.
Ian
Notorious member
Article 2: How I Make Pound Casts
Disclaimer: The following information is the product of my own meandering experience and includes a few original ideas and concepts of my own and some that others have been kind to share with me, and is always subject to change as I learn more. It is in no way intended to be the last word, or...
www.artfulbullet.com
S Mac
Sept. 10, 2021 Steve left us. You are missed.
I didn't go back and re-read the article Ian just referenced, I think I do it the way he described. My little addition would be to fill the case with whatever smaller caliber casting laying around, heat the case with a propane torch to melt before seating the bullet. Saves heating up the casting pot to fill the case.
Ian
Notorious member
I just melt lead in a casting ladle. Heating the case very well with a propane torch is necessary to anneal it and helps get air bubbles out of the alloy you fill it with. If you don't anneal the neck and shoulder area it won't give you true chamber neck dimensions. Annealing the head isn't a bad idea either as doing so will allow the cast to form to the angle of the breech face and be checked for squareness.
Interesting test today. Painted a 300 BO un-sized fired case (LC 14 converted), inserted into 2 different chambers. Mark on case is RIGHT at shoulder -body junction. No marks on the neck, 334 OD + sharpie ink. Neck thickness 12 thous. Yes it HS's but just barely. Load was mid range and not much case expansion. Case sizing with One Shot requires very little force (Lee die). 40k + psi doesn't expand case enough.
Conclusion - chamber cast will add very little useful info. Chamber is big and little can be done about it. Neck can be expanded to take larger bullet dia. to control fit.
Conclusion - chamber cast will add very little useful info. Chamber is big and little can be done about it. Neck can be expanded to take larger bullet dia. to control fit.
Detail. Expander (NOE) 308, sized GC bullet (168gr) 310, mic'd. Fired case OD 0.336 ID 0.312 neck thickness 0.012. So neck expanded 004, assume 002 shrink of brass. Tends to indicate the bullet expanded to 314 before hitting the throat and bore. Saw a lot of lead 'rings' when cleaning these. Theorize: Alloy is getting pushed to the base (expanded to 314), where it is getting cut off by the GC that doesn't expand (as much?). Explains 'ring' attached to mouth. Thoughts? I will repeat with more paint on neck to find real max ID of chamber neck. Also shows that case gauge is not real accurate measuring shoulder position (case length/HS) for setting sizer die. Datum points are different.
Assuming that the chamber does not have a 'step' for the shoulder the only real possibility is the Lee sizer and the chamber do NOT have the same shoulder angle (and even hot loads won't change the fired shoulder to the chamber angle). I also observe the 'rings' of alloy are only 270* so the case is not aligned with the chamber, i.e. case flops around. Case that was sized shows no marks on the case body from sizer, NOT sized down! A chamber pound cast will not show any of these problems!Edit: annealed a case dead soft, flared mouth and inserted into chamber. Mouth is 338 so 336 max neck OD. Minus 012 for neck thickness, bullet should be sized 312. I'll go with 311 for CVA SS and 310 in AR pistol. I don't use bore riding moulds so don't care where the rifling starts.
Edit: AR pistol is 336 neck ID so 310 bullets.
Assuming that the chamber does not have a 'step' for the shoulder the only real possibility is the Lee sizer and the chamber do NOT have the same shoulder angle (and even hot loads won't change the fired shoulder to the chamber angle). I also observe the 'rings' of alloy are only 270* so the case is not aligned with the chamber, i.e. case flops around. Case that was sized shows no marks on the case body from sizer, NOT sized down! A chamber pound cast will not show any of these problems!Edit: annealed a case dead soft, flared mouth and inserted into chamber. Mouth is 338 so 336 max neck OD. Minus 012 for neck thickness, bullet should be sized 312. I'll go with 311 for CVA SS and 310 in AR pistol. I don't use bore riding moulds so don't care where the rifling starts.
Edit: AR pistol is 336 neck ID so 310 bullets.
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That’s interesting. I’m going to do some measuring tonight and see what I come up with from Ian’s suggestion. I have a .408 sizing die so if all the math works I think that’s where I will start.
Took Ian’s measurements and checked it and I am good to a .460 diameter bullet so with groove diameter at .4557 I’m going to try .458. May have to back up to .4575 or .457 but I think .458 will be a good place to start.
Took Ian’s measurements and checked it and I am good to a .460 diameter bullet so with groove diameter at .4557 I’m going to try .458. May have to back up to .4575 or .457 but I think .458 will be a good place to start.
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Getting back around to some of these posts tonight, I have been going over this info again, I have been sizing everything to .458. My max diameter seems to be .460 I haven’t seen the accuracy I was expecting.
What I’m wondering is would I be better off jumping to .459, or just going all the way to .460 I’ve got to buy a sizing die and at the price for a Redding, Id just like some opinions on what everyone thinks. I’ll buy both if need be, I’m kinda thinking go .460 and see how it turns out on the paper.
What I’m wondering is would I be better off jumping to .459, or just going all the way to .460 I’ve got to buy a sizing die and at the price for a Redding, Id just like some opinions on what everyone thinks. I’ll buy both if need be, I’m kinda thinking go .460 and see how it turns out on the paper.
Well I have shot 5 groups from 1200-1900 FPS Lyman 457-193 and 457-124 with no great results, sized .458, using IMR 4198 powder. accuracy is 2.5 inch is the best, averages around 3” at 100 not horrible, but not what I was hoping for. I was hoping to average 2 inches, that may be impossible with this rifle, but one can hope. I have some 457-122 HP that Ive got loaded to try if that doesn’t work out I was going to try a different powder, if that didn’t work I was going to go to a larger bullet size. It’s an HR Buffalo classic. Past the powder change and then sizing to .460? That’s the last ditch effort. If that doesn’t do I will have to reside to the fact it’s a 3 minute gun and will be fun to shooot many years at steel plates at 100-200 yards. 8 inch plates at 200 are still fun. It’s not accurate enough for me to hunt with which is fine I have another that is.
Just trying to squeeze the most out of it I can and leave no stone unturned so to speak.
Just trying to squeeze the most out of it I can and leave no stone unturned so to speak.
Ian
Notorious member
That's pretty good for an H&R. You may have some forearm bedding issues or similar. Those are lightweight rifles with poorly-fitting stocks that kick hard and aren't the easiest to shoot well.
Without digging into every nuance of your loading techniques, I'd consider running some 400-grain jacketed bullets through it while placing the front rest under the very front of the receiver and NOT on the forearm. That should give you a base line if what the rifle is capable.
Without digging into every nuance of your loading techniques, I'd consider running some 400-grain jacketed bullets through it while placing the front rest under the very front of the receiver and NOT on the forearm. That should give you a base line if what the rifle is capable.
That’s not far from how I’ve been shooting it. I’ve shot 325 hornadys in it and about 2 inches is good as it will do after the cold shot goes reall high. This is the 32” heavy barreled rifle my dad has one that will shoot dead nuts around an inch at a 100 this one just won’t. And your right it kicks like a freaking mule. I’m not going to be upset if it won’t do any better, just trying to get the best out of it I can. I’m not concerned about my loading practices it’s the same process I use for my bottleneck and my pistol accuracy tests out of my ransom rest. It’s just going to be I have reached the capability of this rifle and that’s that. I will still load for it and shoot it. Shooting cast was a last ditch effort to find something this gun likes. Sometimes you just have to accept it’s simply that the rifle is accurate enough for the masses but not accurate enough to fit my standards of what I consider an accurate rifle. If it’s just a fun gun to shoot and make a piece of steel really dance then this fits that bill. That 415 grain FP hits like a freight train at 100 and it’s a lot of fun to shoot at 1300-1400 FPS, so I’ll just keep on casting and shooting steel with it. If I can swueeze it down to 2.5 inches at 100 then I will say i have done well.
I still have the 457-122 HP work up left to try. They weigh in about 330grains. So they may shoot some better that the 400 plus have. If not i will take 1 bullet and do a different work up with a different powder and see what the results are. If it’s similar. I will probably just pick the best load with each bullet and move on.
I still have the 457-122 HP work up left to try. They weigh in about 330grains. So they may shoot some better that the 400 plus have. If not i will take 1 bullet and do a different work up with a different powder and see what the results are. If it’s similar. I will probably just pick the best load with each bullet and move on.
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