Fire lapping, I am now a believer

[GaryM]

I've had my whisper now for a few months but I never could get it to shoot very well. 2 1/2 -3" @ 100 yards was the best I could do. I was starting to worry my eyes had reached that stage and precision shooting was a thing of the past.
Well, out of desperation/curiousity I picked up a fire lapping kit (Wheeler brothers kit from Midway) and tried it out.
5 rounds of the 220 grit, 5 rounds of 320 then 5 of 600. Cleaned the bore and ran a dry pacth through, still felt the resistance vary through the bore. I decided I would just run a few patches with the grit on it. 5 patches of 320 then 8 patches of 600. Cleaned it out again and checked with a dry patch, it felt good.
I just got back from the range. Now I am good for 1MOA easily. I only tested at 50yds but I had three rounds overlapping with a fourth opening it to 3/8"!
Needless to say I am quite happy now and I confess I now belong to the firelapping believers club.

Tech info;
16" M4 clone AR w/ Cavarms synthetic lower. Leatherwood qd scope mount.
Sierra 125gr Game master over 19grs of WC1680 (surplus powder) Winchester small rifle primers.
Rifle is a home build with an ER Shaw (M1S) barrel.
Fired off sand bags.

[Flewis]

I think I'm going to give this is a try. The only thing that worries me is that some people seem to think it dramatically shortens the throat life. Anyone think that's true?

[Hoser]

It cant not shorten the life of a barrel.

But if the end result is a more accurate barrel, its a good thing.

Barrels are cheap.

[redtazdog]

Call any barrel maker and they will tell you that fire lapping is not the best way to break your barrel in and hand lapping is the better way if done correct, but shooting more ammo is the best way to polish your barrel.
Fire lapping may wear the throat and the first few inches of the lands if over
done, and how do you tell what is to much lapping?
Many barrel makers and Pro Gunsmiths offer hand lapping for a small fee but they wont firelapp.
Hand lapping may give you a even polish through the length of the barrel.
Firelapping may over polish the throat and first few inches of the barrel before
the last half of the barrel gets ploished.
example take 600 grit sand paper and and use it on a metal surface.
If you use the sandpaper in one long stroke you will see that it has more efect in the begining and less at the end of the stroke.
And barrel are only cheap if you buy cheap made barrels, my 300 whisper barrels are over $400 each and my 510 whisper even more. I figure if I buy the better barrels instead of the cheaper made barrel then I will get what I wanted. The way barrels and all parts are going up in prices I hope I
wont need to replace my barrel for double the price in ten years.

[Pitt300]

Glad others are seeing the "light"
It's worked great for me for years.
I like LBT's products
There is a technique to firelapping & you really should use very soft lead bullets @ subsonic velocities for the best/safest results.
From LBT's website:
http://www.lbtmoulds.com/index.shtml



PUSH THROUGH SLUGS
Price, $8.00 per pack of 20, ship weight ¼ pound
For optimum results with any rifled firearm we consider it mandatory to know the critical interior dimensions which guide the bullet. By knowing the shape and size of a guns throat and bore, the jacketed bullet shooter can more wisely select an appropriate bullet, while the cast bullet shooter can both select the most suitable bullet design and fit it to the gun properly.

LBT BORE LAP KIT
Price, $18.50 ship weight ¼ pound
The current LBT bore lap formula is a highly concentrated abrasive compound
developed and manufactured by LBT specifically for lapping barrels by firing lead bullets which have been impregnated with it.
The lap kit contains very detailed and complete instructions and enough abrasive compound to lap anywhere from 20 to 200 guns, depending on gun type, bore condition, and how liberally it is used. The abrasive compound doesn’t deteriorate with age. This is all you need for 22 rimfires only.

LAP ROLLING PLATES
Price $10.00 shipping weight ½ pound
Precision ground old rolled steel plates used to impregnate bullets with lap
compound to prepare for bore lapping. You can use glass or make your own
whatever size you like. We use a 1/8 x 1 x 4 bottom plate and a 1/8 x ¾ x 6 top plate, which is a ideal size to handle and work with. If you make some, we
recommend you try this size Lap kit instructions tell how to use them.