View Full Version : fire lapping a Krag bore

02-25-2007, 07:28 PM
I am trying to fire lap my Krag bore. It is .310 diameter.
I bought a kitand the bullets furnished with it measure .310 also.The instructions with the kit stipulate usin bullets of .312 or .313 diameter.
I ran 3 sets of 6 bullets through the bore and notice no improvement at all.
With the abrasive rolled into the bullet,it measures .311.Does this mean that I'm not getting enough on the bullet?Should I stop and get larger diameter bullets?
I'm spending about6-8 minutes rolling each bullet.

02-25-2007, 07:51 PM
Kragman, howcum you're lapping the bore? A Krag should be well broke in. How was your accuracy before?

02-25-2007, 08:28 PM
I am in the amen corner with Waksupi... Why? If that rifle barrel is so far gone that you can't get acceptable accuracy with cast bullets, it is too far gone to be brought back to life with laping.

If it will shoot even half way decent, a few thousand rounds of cast bullets will help slick things up.

02-25-2007, 11:22 PM
Thanks for the replies.
Accuracy was1 MOA and is now 2 MOA;thats,OK wth me.
However,it takes 30 patches to clean the bore.That's way more then any other gun that I've ever owned.
I even tried soaking the barrel in Hoppe's overnight,to no avail.I am noow using Sooter's Choice innstead of Hoppe's,bt it is no better.
I can feel a couple of tight spots,in the front 1/3 of the barrel.

02-26-2007, 12:36 AM
Fire-lapping will not take out tight spots. All it can do is smooth up what's there. It has also been demonstrated to open up the leed and the first 2-3 inches of the bore, which is not really a good thing in most cases. I've fire-lapped two barrels, and found no improvement. I don't do it anymore.

If you are trying to work out a tight spot, you will have to rod-lap it. But with an old barrel, that's already worn, it's probably not worth the effort, because the sharpness of the rifling is already gone, and lapping will only make that worse.

Still, it's a chance to practice the craft. The objective will be to get the barrel so the only "tight spot" is just at the muzzle - i.e. the bore is slightly "choked". If taking out .001 or less on diameter will take out the roughness, then it might improve your barrel.

Good gunsmithing books will have a section on how to make and use a rod lap. Roy Dunlap's book is one. The only thing I change is that I've stopped using lead, and started using Cerrosafe to make the laps. The much lower melt temperature makes the job much easier.

02-26-2007, 04:59 AM
I have instructions that came with the firelapping kit that include most of what you said.At my age and physical condition,I have no intrest in lapping by hand.
I would just like to know if the .310 diameter bullets are right for lapping my .310 diameter bore.
If not,I can paper patch or tape with Teflon,to .312 or .313 diameter.
Thank you

02-26-2007, 09:53 AM
Something doesn't sound right here.

1) What loads were producting 1 moa groups?
2) How many did your shoot?
3) Have you changed loads?
4) Was the rifle aways hard to clean or did this develope?

If this wasn't a cast bullet board, I would guess you have let jacket bullet metal fouling build up.

Most if not all of these Krag bores have very fine pitting which produces a "frosted" bore. This comes from corrosive priming. The barrels can be a nusiance to clean. However with good cast bullets and a lube that works, you should not need to clean the rifle for many hundred rounds.

If you have been shooting cast for a while and then gave the barrel a through cleaningnm, there is always the chance the accuracy went south because you removed the seasoning and it will take a number of rounds to reseason the barrel and for accurcy to be restored.

When a 22 LR barrel is clean, it will take 50 to 100 rounds for accuracy to come back.

02-26-2007, 01:03 PM
Sorry to confuse you.
I got the 1892-4 Krag in 1955.It lookeg great and shot great.
Some MOA loads include:43.5 gr 4064 and 150 gr Hornady SP
43.25 gr AA4350 and 150 gr Hornady SP - 41,5 gr 3031 and 150 gr Hornady SP
I have more,but these will be good ones for you to try yourself.
This accuracy remained for many years,but gradually was dissapated.
About 15 years ago I started hunting with various other rifles,and have not hunted with it since.
I cleaned the barrel,and then treated it with the Outer's Foul out System to remove any traces of copper that may have remained.I also gave it the Outer's leadremoval treatment.I only shoot cast in it since then,and the cleaning problem surfaced around that time.
I'm surprised that you asked if I tried any different load combinations.Like most shooters,I shot hundredsof different combinations.
I'm not new to cast bullet shooting.All of my deer hunting,the last ten years,has been with cast bullets.I had a custom mold made and shoot them with paper patched bullets;cast.
I am new to chamber casting and firelapping,and needed help for both.
Hey!in april of 1997,I shot a 5 shot group at 50 yards into 3/8 inch.That was with 22.0 gr 4198 and Lyman 311041GC with Dacron filler.It was still shooting well then.

02-26-2007, 02:39 PM
Kragman.. Thanks for the additional information, that is helpful. Let me just give a couple of thoughts on the matter. I am something of a krag nut. I have two that have been made into sporters (barrels and stocks cut) some years back. I am in the midst of building another from scratch. I have the action and it is now with my gunsmith being rebarreled with a 2 groove Remington 03A3 barrel. I bought my first krag in 1959 and killed my first deer with it in 1960. I paid $15.00 for it and still shoot it on a regular basis. Anyway.. here is my thinking, take it for what it is worth.

1) Krags have barrel groove diamters all over the place. One of mine (1901 vintage ) is .3095 and the other (1895 vintage) is .312. Townsend Whelen wrote of some going as large as .316 in the grooves.

2) I have never met an issue Krag barrel that was not loaded with metal fouling from the jacketed bullets. I have no experience with your Foul-Out system so I can't speak to how well they work. I have always used Sweet's 7.62 and lots of elbow grease.

3) I would guess that the gradual deterioration of your accuracy was due to either accumulated bullet fouling or throat erosian, if we are talking about substantial numbers of rounds. As the throat erodes it often becomes necessary to set the bullets out farther to compensate.

4) Military Krag throats were designed for long 200 grain bullets and those short 150s took quite a jump before they hit the lands, unless they were seated way out in the neck.

5) I have never seen a Military Krag throat that was not eroded to one degree or another.

6) The longer/heavier cast bullets seem to work best as they will get a longer reach into the throat. Even then if they have to take a jump to hit the rifling a harder alloy tends to do better.

7. A larger cast bullet to fill the long and often eroded throat works best, BUT in my rifles cast bullets .313 or larger are to tight for the chamber neck. I neck turn some brass and use .313 cast bullets in the Krag with the larger bore and get very good results.

8) Krags are wondeful cast bullets rifles, but do require some tinkerings

9) All Krags with shoot very well with a charge of 16 grains of 2400 under a bullets that fits well. In fact that is about the only powder charge I use, and if the loads does not do well, then I know it is the bullets. This charge requires no fillers of any kind.

10) As stated previous, most Krag bores are frosted, and it most often they do much after after seasoning with cast bullet lube. It is not a good idea to clean all of this out each time. At most I run two patches weted with Ed's Red down the bore, followed by one or two dry ones. Most often I don't even do this. Unless there is leading or the accuracy goes south there is no need to clean.

11) Is it your rifle, but I don't think fire laping is the way to go. It will only make your bullet fit problems more difficult by enlarging the throat and leade.

Good shooting and keep us posted.

02-26-2007, 03:37 PM
I like your last post,even though it does'nt answer my question.
The cleaning problem never arose before because.like you,I never tried to get the bore "superclean".It surfaced when I,as instructed,cleaned the bore completely between shootings with abrasive on the bullet.
Take my word for it;the Outer's Foul Out System really works.It is a reverse plating system that reoves all copper from the bore.Or lead,with a different solution.
I emailed the kitmaker on the 2nd,and the 5th,and again on the 22nd of this month,with no response.That's why I came here.In the absence of any suggestion,I'll increase the diameter of the bullet with Teflon and try again.
I hunted with the Krag for about 60s years and consider it a true Friend.Now I do all my hunting with a Winchester'94 carbine in 30/30 caliber wth paper patched bullets.All my hunting is in the Big East Woods,and the 30/30 is as good as it gets.
Again,take my word for it,a 170 grain soft lead bulet in a 30/30 kills justnas fast as a Hornady Interlock,and destroys a lotless meat.
check it out.

02-26-2007, 04:09 PM
Kragman... I didn't answer your queston, because fire laping is the wrong thing to do and there is not much sense in telling a fellow how to do the wrong thing.

You are not going to find many, if any, firelaping fans on this board. Silence often sends a better message than word.

But, you are a man fully growed and know your mind. I am not a firelap fan, but if I were in your position and dead set to firelap, I wouldn't use the teflon tape approach. I would get some 312 cast bullets and embed the abrasive in the lead.

That is the best I can do for you! Good luck

MT Gianni
02-26-2007, 04:39 PM
I would ask the kit maker or seller why they sent you bullets at .310 when their instructions state to use .313. Gianni

02-26-2007, 06:37 PM
Hornady makes some swaged bullets in .32 caliber that work well for lapping .30 cal. barrels. However, after I Foul-Outted the very rough bore in my Krag, it shot beautifully with the 314299 sized .311 over 16 grains of 2400. That long nose seems to guide the boolit very well in spite of the rough bore.

02-26-2007, 10:26 PM
Well,I've got it "stuck in my craw"that the two tight spotsin my barrel aredoing me no good at all.The only thing that the 18 firelap bullets did was to identify two,rather then one longer tight spot.
I have never used Teflon but others have,with some success.I just finished wrapping 6 bullets.Tomorrow,I size them .313 and roll thm in grit.
I'll give them a try,and report back here.
Yes,I have been trying to contactthe kitmaker,but,so far,he has not responded.