Fire lapped?
- Thread starter Silverado
- Start date
Usually around 280 to 320 grit compound on cast muliti groove bullets. Cast only to about 12 bn hardness,ie standard wheel weight. A minimum charge of fast powder just to get them out the barrel. And not to be overdone as firelapping can be very productive because it polishes the edge of the rifling which hand lapping cant. If overdone it enlarges throat
Merrill Martin and Neco did a fair bit of work on the subject.
Earlier issues of Precision Shooting magazine discuss it in detail.
Check this link out.
http://www.neconos.com/details2.htm
Brownells carries the kits and we have brought them in for many customers.
Earlier issues of Precision Shooting magazine discuss it in detail.
Check this link out.
http://www.neconos.com/details2.htm
Brownells carries the kits and we have brought them in for many customers.
Handlapping is not rocket science, and much more controllable. I'll hazard a guess that there isn't a custom barrel maker who fire lap their barrels to finish them.
And if Veral is your particular guru, he's published instructions on firelapping in his book as well.
And if Veral is your particular guru, he's published instructions on firelapping in his book as well.
Ask yourself this. When a bullet travels down the bore it is primarily driven by one perpendicular side of the rifling. How does handlapping polish that surface? Since firelapping applies torque to all the same surfaces as normal firing it does
Ask yourself this: how many custom barrel makers fire lap to finish those pricey barrels among those who do lap their barrels to finish?
It would not be difficult to make a fixture to firelap barrel blanks if that were the best way to go. Here's a few names for you: Lilja, Lothar Walther, Spenser, Schneider, Krieger, Douglas, Hart. Going on memory here, I believe they all hand lap to finish their barrels. If firelapping is a superior method, it begs the question why the custom barrel makers charging a pretty penny for their product in such a competitive market don't do that. It would certainly be a hell of a lot faster and save them time, and time is money after all.
It also follows that, when you give your lead lap a few thumps to make it obdurate the barrel, the lead expands to bear evenly on ALL surfaces - including the primary load bearing side of the rifling. In fact, as the rifling is turning the lap much like it does a bullet, similar forces are applied to the lap as are applied to a bullet - it just isn't going as fast and under the same pressure. So yes, the edge of the rifling that you're concerned about does get lapped just fine, thank you very much.
I personally see two advantages to handlapping over fire lapping. First, as you control how far the lap travels, you can lap without opening up the throat/ball seat. Firelapping cuts most aggressively at first point of contact, diminishing as the bullet moves down the barrel; generally speaking, it isn't the throat/ball seat that I'm intent on lapping in the first place. And if it was, I'd make a lap for THAT.
Second, stick a lap in many a factory barrel and you will find tight and loose spots as you move the lap up and down the barrel. Veral Smith and Tom Gray have both said you can detect differences in barrel diameter of as little as 1/10,000" while using a lap - I'm inclined to agree with them although I have no means of measuring that. Using a hand lap, you can start with the tight spots and then move up and down the barrel until resistence to the movement of the lap is uniform throughout the entire barrel. If you try and firelap to that consistency with the kind of barrel that needs lapping the most, you're going to fire a hell of a lot of abrasive loaded bullets through the throat/ball seate to get that consistency. I don't want to do that to the throat of my rifles when it isn't necessary.
Two other things. When you're finished hand lapping a barrel, you can FEEL the consistency of the results in the resistance the lap encounters to movement. With firelapping, you're not really sure what you've got in there - unless you pour a lap to check it, of course. Second, the lap you're left with makes an absolutely excellent cleaning tool for getting your cleaning solutions into the bore.
I don't think firelapping is evil. I just think that, usually, handlapping is a better way to go about it. And if handlapping is the preferred choice of people like Dan Lilja, then that's good enough for a peon like me.
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I'm pretty sure Veral Smith is dead.
- Location
- The Conservative part of Ontario
Check over at grey beard outdoors
Go to http://www.go2gbo.com/forums//index.php
look for the forum "Ask Veral Smith of LBT Q&A"
Veral is the Moderator of that forum
Link to Veral's catalog http://www.graybeardoutdoors.com/lbt/index.htm
Go to http://www.go2gbo.com/forums//index.php
look for the forum "Ask Veral Smith of LBT Q&A"
Veral is the Moderator of that forum
Link to Veral's catalog http://www.graybeardoutdoors.com/lbt/index.htm
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So I was talkin to a ghost two days ago?
Actually Rick if you look at this from the point of view of all the barrel makers you've mentioned, hand lapping is easier than fire lapping FOR THEM, and more over all that is available to them. Firelapping is something done with an assembled gun, or as you say a fixture could be manufactured .....OR they could just have hand lap plugs ,run them in and out as opposed to dealing with the slop of loading compound covered bullets into things they dont have nor want chamber reamers for. You say they all hand lap cause its better. Ya nobody in this era does anything for shear profit huh? Hand bombing is actually easier for the barrel makers
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Fire lapping with cast bullets.
I'm not sure I agree. Lead bullets upset when they contact the lands, this results in a scouring action on the chamber end of the rifling. The scouring effect results in a taper at the chamber end of the rifling that can be very dramatic. On the one rifle that I used lead bullets for I found that the bullets could be out of the case neck about .060" further to contact the lands than previously. I've never encountered that with jacketed bullets.
I'm not sure I agree. Lead bullets upset when they contact the lands, this results in a scouring action on the chamber end of the rifling. The scouring effect results in a taper at the chamber end of the rifling that can be very dramatic. On the one rifle that I used lead bullets for I found that the bullets could be out of the case neck about .060" further to contact the lands than previously. I've never encountered that with jacketed bullets.
Handlapping
I once watched a program on American Shooter (when it was still on our local cable) showing how barrels were made. In one scene they were hand lapping a target grade barrel. The interesting comment was that due to reversing direction of the rod at each end of the barrel the internal diameter would be larger at each end so after lapping they cut several inches off of the muzzle end. The over diameter section at the other end is removed when chambering is done.
So, no, hand lapping is not "much more controlable" if being done on a finished barrel.
From a barrel maker's point of view fire lapping is far too slow and costly to do and has to be done with the barrel fitted to an action. These are the reason why they wouldn't do it.
I once watched a program on American Shooter (when it was still on our local cable) showing how barrels were made. In one scene they were hand lapping a target grade barrel. The interesting comment was that due to reversing direction of the rod at each end of the barrel the internal diameter would be larger at each end so after lapping they cut several inches off of the muzzle end. The over diameter section at the other end is removed when chambering is done.
So, no, hand lapping is not "much more controlable" if being done on a finished barrel.
From a barrel maker's point of view fire lapping is far too slow and costly to do and has to be done with the barrel fitted to an action. These are the reason why they wouldn't do it.
Huh? Sure it is.
I'm not sure I understand where you're coming from. How about giving me a quick explanation of how you do it when you're handlapping a barrel? I suspect your method might be a little different than I and I suspect most other people use.
Having never actually asked a barrel maker why they don't fire lap (and I bet nobody else has here either, but I'm going to within the next couple of days), I don't know whether it is slower or not. I suspect it wouldn't be any slower to turn a groove at one end of the barrel, fix it to a chamber/barrel stub with a drop on collar arrangement, and merrily fire away. My suspicion is that it takes a lot more time to pour a lap and then run a lap up and down the barrel.
I wouldnt use pure lead either!!!!!!!!!!!!!!!!
I would and do use 8-10 cast to 12-13 bn projectiles with 280-300 followed by 6-8 with 400. Using projectiles that are of the right hardness I drive them so as to intentionally stick the first one or two and have the rest basically fall to the ground a short distance from the gun
Rick ,if the barrel maker pushed his lapping plug through and it wasnt attatched to the rod isnt that about how it would come out...As was stated by the above poster, makers dont do fire lapping shearly because it isnt practical for their stage of the operation. They do however end up with an hour glass bore of a tenth or two. I end up with the same tenth or to but its consistantly large to small as from chamber out
