Gunsmith - Crowning the muzzle of a rifle barrel

[fishingonthebottom]

this is an excellent instructional video.

[fishingonthebottom]

this is an excellent instructional video

[OneTimeUser247]

this guy is my neighbor. I can see his house right now.

[damonhawks]

How would you go about removing pitting from an old model 90 barrel? its only on the outside.

the last owner did a real number on it..

[turbo3400]

The brass screw and lapping method will only take any high spots/burrs off of the muzzle. Unless he is using a very aggressive compound and lapped for a significant amount of time, the most material he would be removing is around .001 of an inch. He's not actually recrowning the muzzle, he's just removing any burrs.

This is coming from a certified tool & die maker

[TheKLYPH]

could I still use a brass screw to crown a chrome lined barrel? or should i use a stainless screw?

[MidwayUSA]

@TheKLYPH The purpose of the brass screw, with the lapping compound, is to take the burr off the end of the rifling. We would not advise the use of a stainless screw.

Thanks for Your Business!

[DeRex9]

@slammedls400 And I would just shake hands with Larry for making those great videos :)

[John4566442]

This is an OLD simple trick that nearly anybody can do in their garage.

The way I understood to do this by recutting the crown either on a lathe or by using a piloted cutter by hand. Then use the brass knob/screw to lap the burs off.

Regardless, using a brass ball and lapping compound is a old trick for restoring accuracy. Both Neumann and Traister taught similar methods.

[GunsmithMMG]

Guys I am a certified master gunsmith. Take it from me thats not how its done. In order to recrown a muzzle, you have to strip the reciever of all parts. Then chuck it up in a 3 or 4 jaw lathe chuck about 3 inches from the muzzle tip. Then you'll need to get you a piece of high speed steel tooling and grind you a 22cal crowning tool. A lathe is the only way to be 100 percent sure the crown is perfect. If its not perfect it will send the bullet off coarse

[LostFoxeh]

@GunsmithMMG Just curious, have you tried his brass screw method? I'm with you, it doesn't seem to be a reliable way that will produce perfect results every time. However I have heard that it works, even seen a friend who used a pencil to crown his pellet gun having good results. Maybe in the low powered ranges that is good, or maybe it is improvement but not the best possible. You have the tools right? You should try both and post your findings. Could be fun.

[yahtzee4u]

@GunsmithMMG I think your comment would apply if you were cutting down the barrel and needed to start all over. Larry's gun was simply in need of some touch up, the overall crown shape was still there.

[Rivieratime]

@GunsmithMMG AMEN! This technique may help clean up an abused barrel on a 22 beater for close-up shooting, but for real accuracy you do need to insure that the bore's end (crown) is perfectly perpendicular to the bore so all parts of the bullet's base leave the barrel simultaneously and the gas exhausts uniformly behind it . As you said, that takes proper equipment, typically a crowning tool. Guys-crowns are critical. Even frequent vigorous cleaning from the muzzle-end can ruin accuracy at times

[MaximusStimulus]

@GunsmithMMG Relax.......He is just showing an old simple trick that a novice can do on an old piece of shit firearm. It's not like it's a Lapua Sniper Rifle.

[trushgrrl]

@GunsmithMMG I agree lathe is the only way. I have a machine shop and the way I crown my barrels is to use a gauge pin in the barrel, largest that will slip fit into the barrel for your caliber. Indicate the pin to center using the adjustment screws on the chuck. O.D. is not always concentric with the I.D., not unusual for deep hole drilling. I also indicate in the receiver end via a custom fixture on the other side of the headstock. Then I use the compound to cut the crown.

[TheFallingOpossum]

@GunsmithMMG Why don't you make a video and show us how it's done then. I hate it when people make a negative "I can do it better" comment about a video - and yet not have any videos of their own.

[lj2justgoto]

@GunsmithMMG watch?v=WPS8KyYxuA4

[Nwest82]

@GunsmithMMG I guess this would be better described as "touching-up the crown"

[Money92591]

i have a good winchester model60-22 check out my video

[SphinctersForever]

This video shows re-crowning an old and cheap rifle. Do not do it this way if you have a really good one that has been damaged and needs the crown redone. A good re-crowning is done differently, with a nice cupped shape to the whole end of the barrel and a very smooth and perfectly symmetric radius on the bore hole.  In a really accurate rifle you want the gases to escape the barrel symmetrically, and this hand filing job just isn't the way to do a great job.

[AssassinMan308]

I want to re-crown my air rifle that is in .177 what size screw would I need?

[MavHunter20XX]

Huh....that just seems way too easy.

[njmvermont]

mines like that and still more accurate than my modern marlin.

[fox10169]

could i just use sand paper instead of a file?

[quickcooper61]

@fox10169 Probably but it would take a lot longer, You can get a decent file for not to much money

[whotaughtyou]

WOMANS LEGS

[joeratti]

@slammedls400 lol. im sure he would be grateful

[jassoe]

hello larry, i saw the muzzle of a smith and wesson m29, it has a round muzzle. what does this do? saw it also on a Colt Single Action once.

[Scorpiuszeroone]

The chalk is a great tip!

[GarrettDylan]

What kinda compound is used?

[satan31337]

what an awsome tip man, that video made me sub your chan

[sanity599]

Brownells has a crowning tool that uses a pilot in the bore to keep the cutter at a 90 angle. Then you can use an 11 degree cutter to lower the crown below the end of the rifle. Then you use the screw trick with the lapping compound.

Don't pay any attention to people that say steel jacketed ammo will ruin your bore. They don't know what they are talking about. The steel jacket is way softer then the chrome moly steel of the barrel.

[saisandoval]

Can this be done to a mosin nagant? Please do a video Mr potterfield

[airsoftguy85rocks]

@saisandoval

yes, but get a gunsmith to do it

[jdead6]

@saisandoval Yes! I have an sks that had moderate damage to the muzzle (rough machining due mass-production, nics, gouges, etc...from bad use). Larry's tutorial was very helpful in method to get started. Like he said, use a fine-grain file to remove gross defects from the surface (I also recommend very light strokes and use of a sqare to ensure maintaining 90d angle) , then sandpaper over the file (I use wet/dry with water for precision).

[jdead6]

@jdead6 What I did differently was: I used a fine-grain spherical one-inch grinding bit in my drill, using water for lubricant and friction damage reduction (honing solution works well also, heat and excessive force are your enemy!). For finishing, 400 grit or higher wet/dry sandpaper with water BY HAND (this takes a while). What I ended up with is a near-perfect 12d angle, consistent 360d around the bore (used caliper to measure 12d ring with).

[jdead6]

@jdead6 That might seem like a bit much, but the difference before and after was: 8in. groups at 200y vs. 3in. groups @200y. Huge difference! -Amazing! One other thing I personally recommend, never use the cheap, russian, chinese or east-bloc manufactured ammo. Most of it is steel-jacketed and will destroy the rifling in your barrel after extensive use (these rifles were built for war, and reflect the anticipated life-span of thier user, times and conditions).

[jdead6]

@jdead6 If you are uncertain of your ammo, use a magnet applied to the bullet. They will all appear copper, but the stell-jacketed rounds will stick to the magnet. That's all I have to say, except thanks, Larry! your advice is solid! -happy shooting friend, William. There's the entirety of my coment. -kind of stinks that I have to do this in pieces. Thanks google! you rock. (not)

[baneat]

@jdead6 Start with the last paragraph, like a printer!

[jdead6]

@baneat Dang! (smacks forehead with hand) -anyway, I hope the advice was helpful.

[Iamcartmanxd]

That Model 60 looks a lot like the first gun I ever got, from my grandpa, which he got when he was 12, the Winchester Model 67.

[Sharberboy]

How do I fix a recessed crown?

[blowgunking1994]

Can you do this to a mosin nagant, that had the barrel cut, or do i need to have it completely crownd by a gunsmith

[LockINC]

@blowgunking1994 same principles.

[cannonball666]

He's the wizard of gunsmithing. He's Harry Potterfield.

[manualmaniac1]

@cannonball666 and thats the way it is...

[tmsods]

if a barrel's bore isn't shiny anymore, does it mean that it's dirty? or does it mean that it's worn out? can you fix that without having to replace it?

[luciendentremont]

@tmsods It could be either one. If you run a bore brush with some solvent, and a few clean patches through the bore and there's still no shine, I would say your bore is rusted/pitted and your barrel needs to be replaced.

[paco461]

That's the way it is.

[lowdose338]

I would never do that to the crown of my custom guns! That is atrocious!

[kyle1058]

I am a CNC machinist, would it be better to face the muzzle with a carbide turning tool then use sandpaper on it with a round surface or a round shaped cutting tool, then remove the bur with sandpaper? Just inquiring.. (would probably not do on a CNC, just stating occupation)

[hopecamel]

i cant find wat im lookin for does anybody know if u can have a remington m700 threaded for a flash suppresor without rining the barrel

[xivietal666headx]

Did it shoot a lot better?

[Kahur2007]

i bet that rifle will shoot better now

[Srbija575]

dac308; further, the Brownells hand crowning tool is "supposed" to be self-aligning due to having a pilot for the bore (I don't own one myself). All I am saying is, an amateur is not likely to get satisfactory results with old-time methods, not that they didn't back then, but those old fellows had more patience and skill (typically) than people today do. Happy shooting!

[Srbija575]

dac308 : I know that there have been "old timers" who can work wonders with a file. Allegedly (I say this because I have only read of such things, never met such a person in "real life") whole receivers for guns have been built in this way by truly dedicated people. Having said that, modern tooling gets superior results. I have a lathe (actually, I have 3 of them) and would never trust myself to doing a job like this with a file, let alone using a brass screw and lapping compound.

[mlacey56]

@Srbija575 LOL apparently your not mechanically inclined. Its ok, not all are. A project like this is simple and easy to do correctly.

[Srbija575]

At the risk of sounding really critical, I would not use a brass screw and lapping compound- I would spend the money on a manual (hand powered) muzzle crowning tool from Brownell's which will do a professional job. This tool will work just as well as crowning the muzzle in a lathe, it just takes some effort. Or take it to a gunsmith instead. The old time method shown here will clean up the muzzle, but it will not be square to the bore.

[dac308]

@Srbija575 The brass screw and the lapping compound is only to remove the burs on the edges of the rifling. The crowning itself was done with the file and sand paper. If you work very lightly with the file, you'll get a respectable squared job. Don't get me worng, the tools on Brownells are awesome, I've cut an 11 degree crown on my Marlin 882L which now shoots sub 0.5 MOA. But I still had to be very careful not to lose centre when I was cutting.

[dac308]

@Srbija575 The brass screw and the lapping compound is only to remove the burs on the edges of the rifling. The crowning itself was done with the file and sand paper. If you work very lightly with the file, you'll get a respectable squared job. Don't get me worng, the tools on Brownells are awesome, I've cut an 11 degree crown on my Marlin 882L which now shoots sub 0.5 MOA. But I still had to be very careful not to lose centre when I was cutting - likewise when using the file.

[pyrosimple]

I don't understand how does the end of the muzzle influence the accuracy

[Fentanyl3]

@pyrosimple It has a lot to do with the enormous pressures seen in rifles, anywhere from 40,000 to 80,000 PSI, with pressures that high, even very small nicks and imperfections cause the gases to leave the crown in a non uniform way and just as the bullet leaves the barrel, those non uniform gas flows can affect the projectile as well

[Fentanyl3]

@pyrosimple It has a lot to do with the enormous pressures seen in rifles, anywhere from 40,000 to 80,000 PSI, with pressures that high, even very small nicks and imperfections cause the gases to leave the crown in a non uniform way. Just as the bullet leaves the barrel, those non uniform gas flows can affect the projectile as well.

I have heard of a repaired crown being responsible for over an inch reduction in shot group at 100yards

[deussolinvictus]

@Fentanyl3 Yeah, I've heard of situations where old high dollar sporting rifles ( Winchester M70, or even Mausers for that matter) were re-crowned with a chamfering tool, given a good bore scrubbing, and went back to tiny groups at 100m+. An even and smooth crown does have a lot to do with accuracy. Like you said, any uneven gas disbursement can throw the accuracy to the wind.

[aldexreyes]

@1337chsacker it almost sounds like he says "laughing compund" I was stumped too; I have never heard of such a thing.

[BusterdBodycrab]

@aldexreyes Lapping compound.. A fine grit paste abrasive....

[aldexreyes]

@BusterdBodycrab There you go....you learn something new every day. Thanks Buster!

[xGothimox]

I bet Larry Potterfield could out shoot anyone here.

[semtech30]

Thanks Larry.

I have a brand new .22. It would group a few shots and then produce a flyer.

3 or 4 inches left high or left low. My aim was consistent but the grouping wasn't.

This bore crowning works. I used a cone shaped stone in the hand drill.

Touched it lightly. Finished with a fine diamond fish hook file.

Now my groups are 5 shots in 1 inch at 30ft. No strays.

Must have had a burr on the edge.

I''ve got a tack driver now.

[huntwithairguns]

@semtech30 I hate to tell you this but 1" at 30ft isn't very good with a .22. At 30ft you should get 1/4". What rifle do you have?

[semtech30]

@huntwithairguns Uh........Browning BL. rim fire.

Iron sights only........Just sitting position on the river bank using elbow on knee for a rest. Kinda casual.

Best part is all the little doggies stay in the doghouse now. No strays.

I also filed the foresight to a smaller bead. This helped to.

It's not an ammo problem like some suggest.

Check your guns!

[swdw973]

You can use a marble and lapping compound if you want to do it by hand and are willing to take your time.

Know a match shooter that did this to his match rifles and it kept the crown more even than the screw or the brass tool you can by.

[sssaam17]

hey i have this ruger 10 22 and it doesnt shoot straight because somebody cut about 2 inches of the barrell with the hack saw so if i do these steps will it shoot accurately again?

[nickbownz]

@sssaam17 most likely yes, if they did not recrown it, then that is likely the cause if it's inaccuracy. Use the file the get the face of the barrel perfectly flat, and then proceed like in the video, it should shoot well again.

[GeneralG1810]

Go Larry your the man

[paintballgundown8]

very neat trick

[Acrimonius1408]

Yup.

[callamnffc]

Im not trying to sound and idiot now, but how does this improve accuracy?

Is this the only reason people re-crown barrels or is there another reason?

Thanks

[Theriomalstrom]

As the bullet leaves the muzzle, escaping gasses can push the base of the bullet unevenly if the crown is damaged or poorly finished. A properly crowned muzzle will be as close as possible to perpendicular to the bullet's travel.

[junkiecoyote]

Excellent! I have been wanting to do this to the muzzle of my 91/30 sporter project.

[snipeatchley]

then the principles are the same, you have a projectile and gases exiting the barrel, but on a much smaller scale.  so it would have same effect in theory although it may be minimal, or huge difference because the size and speed of the projectile are ar much smaller.

[nickbownz]

actually, it does have a very large influence on air rifle accuracy, the same way it does on a rifle, I have had air rifles with a horrible crown do 4" groups at 50', which shrunk down to around 1/4" with a recrown.

[snipeatchley]

@MrAirgunlover if your air rifle features a rifled barrel, theoretically yes...

[unitedstatesdale]

Frozen Colgate toothpaste works 10 times better than Lapping compound.

[ewingfox]

hmmm... I would rather use diamond lap of a known grit worth the money considering the value of a job done right!

[phgHunter]

I think these would be more enjoyable if they were higher quality video. I'm sure these are recorded in a lot better quality.

[rooei66]

and thats the way it is

[Migs4000]

lapping compound

[cs2sw]

I will have to say that not everyone has a lathe man, and for some people this method will do just right.

[TescoVee]

You are out of your mind if you think you are not a gunsmith if you don't have a lathe

[ireload2]

That is because you don't know jack about machining or what you can do with a lathe.

[TescoVee]

says you, i know plenty about machining and the capabilities of lathes.

Just remember what happens when you ASSUME!

[ireload2]

Na you don't know jack.

[ewingfox]

@TescoVee ervy gunsmith that I Know who isn't a hack owns a lathe

and knows how to use it. Sometimes,

hand crowning isn't a bad idea because

some rifles index inconsistently with the

receiver, an issue exp. for guns with machined /dovetailed sights

[billcavazos]

Looks like you left the end of the lands exposed. The original muzzle at least had an 11 degree or so cut. It doesnt matter how clean or pretty the crown is. If the ends of the lands are not cut and only polished you could be short changing your trouble. Good work Larry..

[ireload2]

There is an engine lathe in the back ground.

Why don't you use it?

[TescoVee]

because most home gunsmiths don't have one, that's why.

[conglomorateman]

the end of the barrel does not have to be THAT square, its not a sniper rifle, its not a competition rifle. The screw has a round head, he is just using it to make sure the compound is being applied pretty evenly.

Yes its that non-critical of a proceess

[nickbownz]

are you joking? it's an incredibly important process. accuracy means different things to different people, and anyone who isn't poping beer cans at 50' wants a good perfect crown. otherwise accuracy will likely suffer rather than improve.

[websuspect]

If theres pits in the rifle with bullet coming out the escaping gas is going to redirect the action of the bulllet. Might be nice to sand that barrel on a lath, sand the muzzle again recrown it and put it in a soak of parkerizing solution than paint it with gun kote.

[conglomorateman]

the pits on the end are not going to have that big of an effect on the rifle, just like with the other comment its not a sniper rifle, its not a competition rifle either,

you would cut on the lathe, sanding would be pointless if the tool would be giving you a perfectly square cut that you could control down to tens of thousandths depending on your lathe.

[nickbownz]

you are wrong again, sorry. lathes cannot be used for the entire process, you need sand paper or polishing compound to remove the burr on the crown

[stoobers1]

@nickbownz

Seems like after something is cut on a lathe, it ALWAYS needs to be sanded, ground or polished. There are always ridges and grooves, no matter how slow the advance.

Lapping with a ball bearing is brilliant.  Those things are rounder than anything I've ever made.

But how do they make ball bearings?

[nickbownz]

the crown doesn't need to be formed by something that is completely round, just needs to be very consistent the whole way round, so while a ball bearing might be slightly better, it wouldn't fit in the chuck of most hand drills, so a screw like he uses could provide results that are just as good but with hand tools.

[565Customz]

@nickbownz which you can use while its on the lathe...

[ewingfox]

you are right and wrong... I know a v. good gunsmith who keeps the barrel in the lathe when polishing... so he can check/recheck his concentricity and square with dial indicators off the lathe (turning the chuck by hand)

[ewingfox]

@websuspect you cant gun kote a parkerized surface

[websuspect]

@ewingfox Yes you can and it comes out very nice and durable.

[Paladins45]

Thanks to Larry I did as he said in the clip and my 10-22 is running sweet!!

Good on ya Midway!!

[olchevyman]

I could be wrong but isnt that a model 67, im just asking cause it look exactly like my model 67 from 1920something

[daverocker1]

I'd put my money on Larry Potterfield.

[phatmatt7898]

@daverocker1 Because that's the way it is.

[dynosor1]

Plugging the barrel with a cleaning patch or bit of tissue, just below the muzzle would prevent filings and sanding grit from falling all the way into the barrel, bolt and action.

This patch or tissue could then be pushed or blown out the muzzle end when all is done.

If you want the crown to be closer to 45 degrees where the rifling ends, use a ball bearing about twice the bore diameter. Rotate the ball with grinding paste back and forth with light hand pressure to eliminate the burr.

[stoobers1]

Ball bearing?  That's brilliant!

[nickbownz]

well not really... how do you intend to hold it?

[KholdAxe]

how does filing the nicks from the end of the barrel, not even related to the track of the bullet, have any real effect on accuracy? i mean, its not like the scratches are in the barrel

[chadwimc]

The end of the barrel needs to square. The escaping gas can be off if the barrel is not square. Same for the crown at the end of the rifling. Besides, it looks good...

[inetd21]

coelhoteixeira, a lathe wont cut it for making a barrel, first you need to deep hole drill 26 inches of material with less then half a thou run out, then it needs to be cut or button rifled which requires a rifling machine, then you can chamber it on the lathe.

[coelhoteixeira]

Mr.Potterfield,

CAN YOU PLEASE TEACH ME HOW TO BUIL A .25 BARREL.i HAVE SOME MACHINES LIKE LATHE AND OTHERS.tHANK YOU.

[martynbiker]

It's really a "poor mans" gun-smithing technique, it will work, but a lot of the end result depends on the skill of the person wielding the tools.......if your a ham-fisted neanderthal then you will do more damage than you are trying to repair.

[erklaerbaer01]

i would prefer a lathe and a reamer

[zacharyworr]

sweet.

[gnigged68]

With a cnc machine lathe11!!!11!

[Bottleshooter8]

Just out of curiosity, how do you re-crown a rifle muzzle?

[alderaforall]

you jam it into the nearest concrete driveway you can find, one muzzel recrowned

[BORDERTRASH01]

I've tried that! lol