I just was told by a reliable source not to fire lap my new barrel. He told me that they have information that shows a throat can be moved forward as much as much as.125. Sounds logical to me, has anyone else heard this?  

I haven't tried it yet, but this is from NECO's web page...
-------------------

"NECO Pressure (Fire) Lapping ™ laps a barrel under continuous pressure. The bullets maintain full bore contact, which gives optimum results. With the NECO process, tool marks that remain in the bore after mass-production boring and rifling are either eliminated or significantly reduced in magnitude--meaning that cuts into the bore surface may remain after projections from the surface are removed. Metal removal from the bore's groove diameter is less than 0.0001 (1/10,000th) inch. The NECO process also smoothes up the pressure edges of the rifling lands."

[url]http://www.neconos.com/details2.htm[/url]

-----------------

Since you're fireing abrasives through the barrel, It would be possible to screw things up.  I don't think that if you go to a respectable source and follow the directions, that you'd have to worry about that kind of damage though.

Firelapping isn't a job for the hack.
If you use too much grit, or follow the wrong progressions with your grits, you can not only mess up the throad, [i]but you can completley alter the internal dimensions of your barrel~![/i]

The easiest way to tell is you are able to do a firelap job yourself is to go out and buy a little toy model car, and put it together....

If you followed the directions word for word, you shouldn't do a fire lap job on your rifle. It requires too much analysis and critical thinking.
You have to say to yourself

"Hmmmm.... Should I fire another run with a mild grit? Or maybe should I fire 3 runs with a light grit?"
and then make the decision.
If you are wrong, you screw up your barrel.
It is probnably best to either have someone do it for you, and watch them roll the different grits, and pay attention to the progressions and velocitys they use...

Then, once you have the fundamentals down of "what to do" and you know "what the objective is" you can try it yourself.

[uzi] [b]EXPERTS[/b]

Oh yeah.

Once you do yours, and if it all turns out well, try shooting your best handload out of the gun, only [i]moly coat[/i] it...

Once the internal tool marks are removed (or minimalized) and you fire rounds with the added lubricity of molycoat, you will see an improved  shot to shot consistency develop.
Without the tool marks imparting purchase on the projectile, it allows the rifling to gain more hold, and deliver a more consistent shot, since it now dosn't have to deal with the added element of tool marks altering the bullets path.

[uzi][b]EXPERTS[/b]

.125 sounds like alot to me. but then it depends on the grit of the lapping compound(coarse or fine)etc. and how many times you fire lap. 3-4 shots should be enough to get the burrs out.unless you have a problem barrel....also use reduced power loads and lead bullets when fire lapping....Personally I perfer hand lapping, You have more control of the process.

Sounds like you've done this before, or at least are familiar with the process.  I was thinking about purchasing the precoated bullets already loaded in a round, and following their recommended numbers of each for a particular rifle.  

Makes life a little simpler for me since I believe the company that tests their products would know.  I'd think the biggest problem would be determining which company and products are the most reliable and consistant.

If you've tried the process, how were your results in accuracy improvement?  Thanks.

David Tubbs dosent seem to think so.
Try his Final Finish fire lapping kit.
Arizona ammunition sells it preloaded.

Firelapping can be used to prolong the life of a shot-out barrel.  If groups are starting to open due to throat erosion, firelapping will smooth the eroded throat.

Last month I used a 5-step Final Finish loaded ammo kit from Arizona Ammunition.  I tried it on a new 24 inch SS Wilson barrel.  Groups tightened roughly 30 percent.

For firelapping to actually hurt your groups, you have either a quality hand-lapped barrel from a competent riflesmith (in which case you should NOT firelap without consulting the maker) or a barrel with more problems than can be corrected without major surgery.

Firelapping is, in my experience, an inexpensive way to add quality to a barrel and avoid the labor of hand-lapping.

Stealth) My experiences with it have been amazing, and I am going to do it to all my precision bolt rifles.

I used the NECO lap, and tinkered around with different speeds and grits using a $100 surplus Enfield I had, just to try it before I did it on a gun I cared about...

The instructions for the NECO lap are pretty much dead on the money, but I think the amount of abrasion you want to use should be in line with the condition of your barrel, be it now, or well shot. The instructions are a good guidepost to follow, but since gun barrels are individual, there can be no monolithic set of directions of how to treat them with fire-lap.

Arock hit the fly on the nuts when he said you probably don't want to take a gun with a match barrel already shooting 1/2 MOA and fire-lap it. I brought a $400 FFL box stock HOWA Police Counter Sniper .308 HBAR from shooting an average of a bit on the heavy side of 3/4 MOA with factory Federal match ammo,   down to 1/2 MOA, and often 1/4 MOA if the conditions are right and I am shooting that well that day.

This was after fire lapping, glass bedding, and shooting molycoated handloads (Not to mention a Leupold that cost more than the gun)...

I believe in it.
But then again, the BOSS system and Cryo-Accurizing make sense to me too, where such things too new-fangled for some geezers who will swear they don't mean a damn thing.

My .02

[uzi][b]EXPERTS[/b]

Anyone have the link to Arizona Ammunition.  Just ran a search and came up empty.

Thanks

Ok.  You got me interested.  Just what is fire-lapping?

www.azammo.com

Talk to Valerie or the owner James Schmidt.  Valerie's a honey.  Tell her Arock said Hi!

GunTests gave a very good rating to NECO. I plan ti try it laterr to a few of my rifles, the Enfieeld goes first

When the guy at Sinclair International told me this, (I didn't get his name,) that all the information they have on fire lapping says don't do it, I believe them. These are knowledgeable people, but I must admit when he told me fire lapping (could) move the throat back as much as much .125 I said to myself, no way man, that is a lot of metal. But than I thought in the case of a 300 mag or larger it could happen. knowing when to stop, and what to watch for probably is more of a guessing game for the average shooter, a video should be sold along with the kit to give a better understanding of the process. I think it is great we have a place to  discuss topics like this, I appreciate each of you comments.

.125 sounds ridiculous to me, even allowing that each .001 removed diameter-wise would actually advance the cone of the rifling origin more than .001.

I've almost worn my fingers down to the bones trying to remove .001 or so off of small steel parts with various grit abrasive papers. I don't see how the fine abrasives used for fire lapping could do this.

.125" back in the throat??  .05" is bad enough...but .125" is insane, and NOT acceptable!  You would need longer bullets, you would get different pressures and lesser velocities for EVERY load because the bullet would be so far away from the lands.  The jump space would be phenominally long, and no bullet of any OAL would stabilize sufficiently in a throat that far back.

At least for a target shooter, this process sounds very, VERY bad, and it's slight beneficial effects will in NO WAY make up for all of the loss in groups and long-range accuracy that will come of it.  If you don't believe me, take this subject to the Competitive/Accurate AR board...and be sure to wear your flame suit!

[img]www.auburn.edu/~littlcb/new jew.jpg[/img]