New barrel break in

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Wayne S posted this 28 March 2010

I just  installed a new Savage  {OME} heavy weight barrel  in 308 on my switch barrel Savage rifle. This will be a deciated cast bullet only barrel and potentional “postal match” set up.

Are there any tricks to a new cast bullet only barrel break in ??

 

Wayne

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RicinYakima posted this 28 March 2010

FWIW, when I bought my Savage FP10, I shot 60 rounds of NM 7.62 NATO to fire form the brass. I shot 10, couple of patches of Hoppe's #9, let it soak a couple of minutes, dried and shot 10 more. Cleaned and de-coppered the barrel down to bare metal, patched with Fliz for about 10 passes. Since then have been shooting cast for 8 years with just a wet Ed's Red patch and two dry ones. Seems to be as smooth as they make them. Ric

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Wayne S posted this 28 March 2010

Thanks, I'll reshearch Ed's Red Patch's

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Wayne S posted this 28 March 2010

Just wondering everyones thoughts on filling a couple of the lube groves with JB Paste or valve polishing compound and fireing them at sbout 1200 fps followed by several “fritz ” lubed bullets ?? followed by the usual cleaning ??

But I think I do have 50 or more old pulled military bullets I could use ??

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DAMRON G posted this 28 March 2010

I have done the JB in lube groove trick on old military rifles and it worked well to get the crud out.I brake in barrels by shooting them and seeing how they do first. If they shoot good don't worry about the “ritual” barrel break in in my opinion.

George

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RicinYakima posted this 28 March 2010

The concern I have with firing a bullet with abrasive is that you have no control of lateral pressures. It could make a oval or unknown shape to the throat. While I have done it, it was a last resort. For the length of the bore, I have used Ken Mollohan's (Molly in the CBA and on the net) guidance of using a cloth wrapped brass bore brush and using it by hand. Ric

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Wayne S posted this 28 March 2010

:dude:K.I.S.S.  Me like that

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DAMRON G posted this 28 March 2010

RicinYakima wrote: The concern I have with firing a bullet with abrasive is that you have no control of lateral pressures. It could make a oval or unknown shape to the throat.  

I have done this in about 10 rifles and havent seen any problems,but i only shoot the bullets with enough powder to just get them out of the barrel.When i was using a NECO firelap kit i did wash one throat out with cast bullets trying to clan up a rough spot in a barrel.I then found out from a friend that he switched to jacketed bullets for lapping to resolve the issue caused by obturating cast bullets..At least its a good use for jacketed bullets<G>

George

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CB posted this 29 March 2010

Wayne, the talk about jacketed bullets I also agree with.

I know a past cb shooter who did tests with many combinations of fire lapping. He used a bore scope to inspect each test. The best results was with 2 or maybe 3 shots with the heaviest jacketed bullet at a low velocity. He also found that 400 grit creates about the best results. Very fine polishing of the bore isn't necessary as that will cause higher friction and heat. The purpose is to only knock down any burs or loosen a slight tight spot.

The only other grit I use is 'JB Bore Bright' bore cleaner. It is a garnet based compound which is the safest grit for bores. I've used 6-7grs of Unique with a 200gr jacketed bullet in my 30 calibers...............Dan

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JetMech posted this 30 March 2010

I broke a 2 groove Springfield barrel last week. I had loaded 9 rounds of a 180gr bullet over a starting load of IMR4350. Decoppering after every round and using ed's red w/lanolin after, by the forth round, the barrel was noticeable smoother. In fact, it felt as smooth as my hand-lapped Badger barrel. I shot a fifth round but decided the others weren't needed. Done.

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Wayne S posted this 30 March 2010

Dan Willems wrote: Wayne, the talk about jacketed bullets I also agree with.

I know a past cb shooter who did tests with many combinations of fire lapping. He used a bore scope to inspect each test. The best results was with 2 or maybe 3 shots with the heaviest jacketed bullet at a low velocity. He also found that 400 grit creates about the best results. Very fine polishing of the bore isn't necessary as that will cause higher friction and heat. The purpose is to only knock down any burs or loosen a slight tight spot.

The only other grit I use is 'JB Bore Bright' bore cleaner. It is a garnet based compound which is the safest grit for bores. I've used 6-7grs of Unique with a 200gr jacketed bullet in my 30 calibers...............Dan Dan,

Thnks, did your friend use the J-bullets by them selfs or were they coated with the 400, OR did he just “scrub” the bore wirh the 400 grit and a tight fitting brush or mop. or put it in a greese groove or two on a bullet like a 311466

As to the JB Bore Bright, I think I read somewhere here to coat the bore with JB and then fire a low veloicy  over size .310 for a 308 bore {?}> bullet.??

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CB posted this 30 March 2010

Wayne S wrote: Dan,

Thnks, did your friend use the J-bullets by them selfs or were they coated with the 400, OR did he just “scrub” the bore wirh the 400 grit and a tight fitting brush or mop. or put it in a greese groove or two on a bullet like a 311466

As to the JB Bore Bright, I think I read somewhere here to coat the bore with JB and then fire a low veloicy  over size .310 for a 308 bore {?}> bullet.??

All lapping bullets should be rolled into the compound you are going to use. I know shooters who say they are getting good results by filling grease grooves on CBs or by leaving compounds in the bore and shooting, but I don't think that is the correct way. Leaving loose compounds on the bullet or in the bore can cause a hydraulic effect and cause the lateral forces (as Ric states) or waves as the bullet travels down the bore causing inconstant polishing.

The grit needs to be embedded into the surface of the bullet to be carried the length of the bore. JB is harder to embed than 400 grit compound. When I use BoreBright I still roll the jacketed bullet between 2 plates of glass, but may leave the surface as-is and not wipe it dry. If you coat the bore with JB, use a dry patch (no liquid cleaner) leaving behind the least amount in the bore.

Like Dollar Bill states, it is simple enough to do like you say KISS. You will not get much of any results lapping by hand with a patch or mop. Hand lapping is done with a bore slug and is difficult to do and to achieve the right results. A barrel can be ruined by over fire-lapping so care is needed to watch the condition like Dollar Bill did..................Dan

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amb1935 posted this 30 March 2010

I fired about 20 rounds of mothers mag polish vocered CBs with reduced loads out of an old m91/30. I wasn't happy with the bore condition but wasn't reallyscared to mess anything up. Keep in mind, that is not nearly as aggressive as 400 grit compound. It polished the bore up quite nicely.

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canalupo posted this 30 March 2010

Most barrel break-in information is a myth. The only time anyone should shoot a bore polishing compound in a barrel is if there is a noticable rough spot. The rough spots are usually due to slop in barrel or rust. A derusting agent (not naval jelly that has acid in it) swabbed in barrel and super cleaned is the most a damaged/rusted barrel requires. All barrels will polish and break-in nicely just from shooting and keeping them clean during the first 100/200 rounds or so. save time and aggravation and enjoy shooting that will do the job.

Check the shilen barrel website or any reputable barrel maker and you will probably get the same advice.

My two cents and I'm sticking with it.

Good luck

Bob D

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argie1891 posted this 30 March 2010

was at the range when a shooter was breaking in a new rifle. What fun shoot one shot clean for 5 min. shoot a shot clean shoot clean shoot clean. i dont mind the shoot part but spending 3 hours shooting a box of shells just isnt my bag. the kicker on this he was breaking in a marlin lever action in 44 mag. how much better could he make it? I think that the manufactures use their break in as an excuse if the rifle dosent shoot they can always blame the purchaser for not following the directions exactly. joe gifford

if you think you have it figured out then you just dont understand

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JetMech posted this 30 March 2010

I've seen hundreds, if not thousands of machined parts over the years. It's a pretty rare case where one comes out of the machine, even cnc machines or water jets, where they do not require some degree of deburring or other cleaning up, besides degreasing. I did look up a couple barrel manufacturers and most recommend some barrel break-in. The exceptions are those that hand-lap barrels. Yes, I spent 4 hours breaking in a barrel, but it was one shot, put the rifle down, shoot 10 CBs fron another rifle, run a couple patches thru, shoot one, 10 CBs from another rifle, etc... I've just spent, total actual time, about 1 hour to ensure a factory barrel will deliver the best accuracy possible, for as long as I have it, which will be in the neighborhood of 30 years and will see thousands of carefully cast and handloaded rounds thru it. I hour work......30 years of confidence....it's a no-brainer to me.

Lapping compounds: I won't do it. Ed Harris recommended I run a tight patch with Bon Ami in an old bore to clean it up. Worked like a charm. No throat or muzzle damage. Different suject, though. Wayne was asking about new barrel break in.

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CB posted this 30 March 2010

Dollar Bill wrote: I've seen hundreds, if not thousands of machined parts over the years. It's a pretty rare case where one comes out of the machine, even cnc machines or water jets, where they do not require some degree of deburring or other cleaning up, besides degreasing.  Wayne was asking about new barrel break in.

That's right, Wayne was asking about an (OME) Savage barrel. There is quite a difference between what Shilen makes and what Savage makes. There most likely isn't any need to lap a custom barrel, but production firearm barrels are a different thing.

Caffee, the most re-known 22 rimfire riflemaker says the worst thing about shooting the lead bullet 22s in the machine marks left in the barrel from cutting the chamber and throat. It won't go away by just shooting.

I've never heard a bad thing from the any of the Production Class shooters who have done a jacketed 2 or 3 bullet lap and only praise the quality of their barrel afterwards............Dan

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muley posted this 30 March 2010

on the subject of barrel breaking in, Roy Dunlap in his gunsmithing book suggests firing about 100 rounds of lead bullets, for the same effect as using a lead lap by hand, also much easier and enjoyable

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mlr1m posted this 09 December 2010

Hand lapping is great. Its also time consuming and hard work. If done correctly it will be perfect from end to end. Fire lapping is just the new microwave quick fix. I do not see how it can have the same effect the whole length of the barrel as it does at the throat.

Michael

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CB posted this 09 December 2010

It seems logical that fire lapping would have more effect nearer the chamber and less towards the muzzle. I have heard it claimed that that was true.

I had a barrel that had a loose area in the middle. The bore was tight on a lead slug for the first 8 inches or so and then there was little or no resistance until about an inch before the muzzle when it tightened up again. Slugging near the muzzle and an inch ahead of the throat gave about the same dimensions. I had no way to measure the diameter in the middle without sawing the barrel in two.

I reasoned that if most of the effect of fire lapping was near the chamber I should be able to enlarge the back of the bore so it didn't size down cast bullets early and then let gas by in the middle causing fouling.

I fire lapped and slugged both the bore ahead of the throat and the “choke” at the muzzle. When it became obvious that the fire lapping was enlarging the bore at the muzzle at least as much as at the rear I stopped. What are the experiences of other fire lappers?

John

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Scearcy posted this 24 February 2017

I was going to start a new thread and the forum software brought up this old thread. I have an unfired factory barrel that I am going to put on my Remington 700.  The barrel is a 243. In general I am a member of the camp that prefers to clean my barrel after every 20 rounds during a match. Remove any burrs, facilitate cleaning, etc. In the past I have lightly (5 rounds or so) fire lapped a couple of barrels. One was a Springfield and the other was a Savage CM.  I wasn't aware of the risks and I was satisfied with the outcome.

The new barrel is SS and I have grown a bit more cautious about damaging a barrel. Thoughts?

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