Fire Lapping a Barrel

[br45zy]

I have a 300 RUM that may be a candidate for it and I am looking for some shooters with first hand experience fire lapping a barrel and the results they saw.
My opinion has always been to not do it but this rifle has been a little frustrating. It's factory Remington barrel that has less than 100 rounds through it and copper fouls badly after only three to four shots, enough so that accuracy noticeably drops. Clean cold bore and second shot accuracy is very good and consistent. I had it bore scoped and it looks OK from end to end just not great.
Thanks for any help or advice.

 

[CliffM]

I did my 30-338 that has a tight bore, .298. The barrel was rough as a cob, it shot well enough but was a bear to clean.
I used the Tubbs kit and all the bullets in it, even followed the instructions
It now shoots the same load at about 200fps less and does not foul the first 18". The remainder has so little fouling that just a few patches will clean it right up.
Accuracy is noticeably better with far less fliers.
Cliff

 

[tradbowhunter]

I would have thought it would shoot faster....

 

[J E Custom]

I have a 300 RUM that may be a candidate for it and I am looking for some shooters with first hand experience fire lapping a barrel and the results they saw.
My opinion has always been to not do it but this rifle has been a little frustrating. It's factory Remington barrel that has less than 100 rounds through it and copper fouls badly after only three to four shots, enough so that accuracy noticeably drops. Clean cold bore and second shot accuracy is very good and consistent. I had it bore scoped and it looks OK from end to end just not great.
Thanks for any help or advice.

I personally Never recommend fire lapping is a last resort because it laps the throat and does very
little for the rest of the barrel.

The fact that the barrel shoots good the first couple of shots tells me that you need to do a good
break in.

Do a shoot, and clean after every shot for 20+ rounds and you will start seeing an improvement
on the fouling issue. It takes time and patience but is it worth the effort and improves the entire
bore not just the throat.

As you shoot, you should start to feel the improvement in the bore and the number of patches
to come clean should drop to 1 or 2.

It is not unusual for factory barrels to take more than a custom barrel so don't take a short cut
and start firing 2 or 3 shots and then cleaning. The purpose of the shoot and clean method is to
shoot 1 bullet in a clean bore and let it smooth the barrel out evenly end to end.

Fire lapping enlarges the bore at the throat and reduces bullet fit causing lower pressure and velocity.
hand lapping can do this if it is over done breaking it in only wears the high spots and fills in the
machine marks left from the rifling process.

Some custom barrels are very tight even after lapping because the barrel maker allowed for this
and reamed and rifled the barrel .000001 undersized.

J E CUSTOM

 

[newmexkid]

I did the Tubbs thingy on a 300 Win. and never noticed any difference one way or the other.

 

[Tikkamike]

I have done 3 rifles and am waiting on the bullets to do it to a 4th. The first 2 I did it on were Winchester model 70 super shadows, one in 270wsm and the other in 7wsm. and it made an amazing difference on both, the cleaning became very very easy and both were tack drivers afterword. the last one I did was a 700cdl in 300 win, the barrel wasn about average on fouling but it shot like crap, i did a good break in, had it bedded recrowned checked mounts and scope etc... ran lapping bullets in it and no change.. I have a 700 in 375 rum that is doing exactly what your rifle does. it shoots awesome for 3-4 shots then it fouls horribly, pressure starts to come up... its horrible. so im going to run some final finish bullets in it and see what happens... overall i do think its kind of a last resort in ways but i truly believe they can make a world of difference

 

[7mmRHB]

br45zy, I've done over 100 break-ins on factory bbls with the Tubbs Final Finish bullets. It works amazingly well every time, if done properly. First of all, buy the TMS kit which consists of the same grit as the #3s and #4s out of the Final finish kit. You don't need the coarse #1s and #2s unless you have the worst factory bbl on the planet. I have only used the # 2s on two bbls ever!! The TMS kit contains 50 bullets so you can get two break-ins from each kit. Use a light charge of RL22, For a 300 RUM ,about 79 grns if the bullets are 175s and 78gr if they are 190s or 76 grs of H4831.Seat the bullets with plenty of jump to the rifling ( .050 or more ). Always shoot the first shot over a light layer of Kroil in the bbl. Shoot 5 then clean spotlessly ,lightly swab with Kroil and shoot five more and so on until done. It will be cleaning in a couple of patches by the last cleaning. Never fire a tubbs bullet down the bore if the bbl is more than just warm to the touch. Just blasting away without cooling the bbl is why most people think that the tubbs kit doesn't work, or takes out your throat!! I have done more than 50 RUMs and they always show great improvement in SDs, ES and accuracy and it takes 2 more grs of powder to get back to the previous max pressure but with increased velocity. Don't let anyone tell you the don't work or that they harm your bbl because if you do it right you will be happy!! ---- RHB

 

[J E Custom]

I have done more than 50 RUMs and they always show great improvement in SDs, ES and accuracy and it takes 2 more grs of powder to get back to the previous max pressure but with increased velocity. Don't let anyone tell you the don't work or that they harm your bbl because if you do it right you will be happy!! ---- RHB[/QUOTE]

I agree to disagree with this and I will tel you why.

I have only done 1 and that was enough for me. I have hand lapped lots of barrels when they had poor
accuracy. One barrel was so bad I figured, what did I have to lose because the next step was
to replace it (It would not shoot less than 5" groups at 100 yards ). I throughly inspected it with the bore
scope so I could compare the results and even cast a broach to check the bore size after the
fire lapping.

Having this barrel to sacrifice if I couldn't,t fix it, I followed the instructions to the letter and waited
5 min between shots to give the barrel time to cool down.

After completing the fire lapping and still at the range and good cleaning, I fired the best loads I had
for it before it was fire lapped and it did improve to around 3'' groups and it did drop in velocity.
It was better in every way but it was still not good enough to save the barrel from being used as
a tomato stake.

After getting it back in my shop and inspecting it again with the bore scope most of the machine marks
were gone from the throat end but very little had been changed on the muzzle end.

Inserting the broach I cast earlier I found slight resistance at the muzzle but none at the chamber
end. Not wanting to give up on the fire lapping I cast a broach at 1" from the chamber end and
that's when I decided never to use that system on any rifle that was to be used for more than 100
to 200 yards because of bore taper. the lap would not go but 4" or 5" toward the muzzle .The only
thing that helps is the fact that as the bullet moves down the barrel it gets tighter.

On this site everyone worries about barrel life and this method has to take several hundred rounds
off the barrel life (Lower velocity and 2 or 3 more grains of powder to regain the velocity, only
enforces the end results) .A tight, smooth barrel normally increases velocity.

I would never tell anyone that they shouldn't do something, I just tell what I have seen and prov en
to my self and if they chose to do something else good luck to them.

My test was a worst case scenario and with a better barrel I am sure the results would be better from
an accuracy standpoint but to purposely remove several hundred rounds of barrel life from a barrel
just doesn't makes sense especially on one that shoots well, but fouls after 2 or 3 shots.

This is just My experience with this system and the explanation for the reason that I don't recommend it.

Nothing personal.

J E CUSTOM

 

[7mmRHB]

JE, sounds like you used the whole kit!! As I said that's a bad idea. 5 minutes apart on a ten shot string is not going to keep the bbl cool enough. The last three or four shots were doing damage, especially if you were using the 1s and 2s. If your load was at 2900 fps or higher you were doing damage. I try to keep the load between 2500 and 2800 fps for the best results. The velocity decrease is from a very slick bbl, the same as you would get from using Moly or Tungsten disulfide.I haven't noticed any of the other complaints you have mentioned. We have put together hundreds of factory rifles using Tubbs final Finish, Great pillar bedding, great brass work and great load development ( Good Grouper ) to make great shooting,long range hunting rifles that will shoot sub MOA at a 1000yds or more!!! Tubbs Final Finish works if done correctly!!!! ---- RHB

 

[Alchemist]

A couple months ago, I used a Tubb FF kit (#1 thru #5) on a Factory Remington CDL 30-06 with the fly rod sporter barrel. Before using the FF kit, the rifle would shoot no better than a 2 1/4", 5 shot group at 100yds. The bore would also visibly copper foul after just one or two rounds. After 132 rounds of factory ammo through the barrel and one poorly placed shot on a whitetail last fall, I was resigned to a re-barrel job or to sell the gun. That's when someone suggested the Tubb kit.

I used the .308 Tubb kit and followed the directions to the letter. It took 2 weeks to get it done but the difference was obvious - just under 1 MOA at 100 with the same box of factory cartridges. Plus, the copper fouling cleans up with just a couple wet patches of BT Eliminator.

Since I use this rifle at considerably shorter ranges than most on this forum do their rifles, I'll consider this one done, as long as it will hold the < 1 MOA. And with the cost and scarcity of ammo and components to reload, I won't be shooting it much except during hunting season to fill the freezer.

The take-away from this experience for me has been as a last resort, why not? On a custom rifle with a aftermarket barrel, built to tighter tolerences, unless it is copper fouling excessively, the problem is more likely something else.

 

[br45zy]

I appreciate everyone's input. My uneducated guess was that most of the lapping would occur in the throat and first third of the barrel because most of the compound on the bullet's jacket would abrade off the bullet before it exited the muzzle.

I'm ok with the accuracy of the rifle as it is but not thrilled with it. Now throw in the fact that I can't get more than 3 or 4 shots before it has to be cleaned and I've decided to use this rifle as a test bed. If fire lapping works and I can get the accuracy and performance out of it I want then I will continue to shoot it as it is. If it does't show the improvements I want then I have barrels in the safe that I can use to turn this one into either a 7 LRM or another 300 RUM.

I'm going to document the current load I'm shooting, muzzle velocity, accuracy and free bore both before and after then let the numbers decide what happens next.

Thanks again for sharing your experiences.

 

[tradbowhunter]

I can hardly wait to see the results, i'm waiting on a 6mm improved....should be done in a couple of wks, the barrel is a kreiger 8 twist, and i was going to run the tms kit with it...As per david tubbs instuction.....

 

[Bart B]

I don't think a Kreiger barrel needs to be "conditioned" in any way. Too many folks have shot them as is and won matches setting records doing so and so on and so on.......

Nor does any other barrel need to be "conditioned" if it's made right. If it ain't made right, why buy it in the first place?

Any time the hole in a barrel's made bigger, there's less resistance to the bullet starting down it and pressure will be less. So will muzzle velocity.

Every "rough" bore barrel I've shot produced better accuracy after a few rounds laid copper in those rough spots so subsequent bullets would not be unbalanced from jacket material being scraped off. Never ever had one that had accuracy get worse after copper fouling.

The most accurate barrels I know of all have the same bore and groove diameters all the way from leade to muzzle. No taper whatsoever. Good barrel makers lap barrels to less than .0001" spread the entire length of the rifling when the blank's finished. Fire lapping a barrel makes it taper tighter from its hind end forward. Borrow a Sheffield air gauge then measure your fire lapped barrel.

 

[J E Custom]

I don't think a Kreiger barrel needs to be "conditioned" in any way. Too many folks have shot them as is and won matches setting records doing so and so on and so on.......

Nor does any other barrel need to be "conditioned" if it's made right. If it ain't made right, why buy it in the first place?

Any time the hole in a barrel's made bigger, there's less resistance to the bullet starting down it and pressure will be less. So will muzzle velocity.

Every "rough" bore barrel I've shot produced better accuracy after a few rounds laid copper in those rough spots so subsequent bullets would not be unbalanced from jacket material being scraped off. Never ever had one that had accuracy get worse after copper fouling.

The most accurate barrels I know of all have the same bore and groove diameters all the way from lead to muzzle. No taper whatsoever. Good barrel makers lap barrels to less than .0001" spread the entire length of the rifling when the blanks finished. Fire lapping a barrel makes it taper tighter from its hind end forward. Borrow a Sheffield air gage then measure your fire lapped barrel.

Thank you Bart !!!

I was beginning to think I was the only one that did not abuse barrels. I have re barreled many barrels that had been abused one way or the other and hate to see a quality barrel like the Krieger Fire Lapped.

I know that seasoning or breaking in a barrel takes time but it is well worth it. (There is no free
ride) taking short cuts leads to bad things. That is the big difference between a good smith and
a bad one.

To save money a person that though he needed to lap a barrel used the rubber abrasive tips that
are used on a Dremel tool to "Fire Lapp" his barrel. When I bore scoped it, it looked like it had been through two wars. It ticked me of to see a fine barrel treated this way so I declined to re barrel It
not knowing what he would do next.

The logic is very simple, "ONCE YOU REMOVE BARREL MATERIAL YOU CANT PUT IT BACK" And if you taper the bore it is worthless. Barrel makers go to great lengths to Gage bore diameter and most
reject them if the barrel has more than .00005 difference end to end.

Gun smiths and barrel makers rejoice , this means more barrel jobs and faster barrel burn outs.

PS : I did follow the instructions to the letter and 5 min. between shots (1 hour and 20 min is plenty
of time to allow the barrel to cool for 10 shots. And everyone that wants to try it should, that way,
they can learn the hard way. I promise not to try and talk anyone out of doing this anymore In fact I should encourage it because it is job security for lots of gun smiths.

As my signature states "Press ON"

J E CUSTOM