bullet prep for fire lapping

[oley55]

bought the NECO fire lapping kit and have reread the directions a couple times, but it does not go into detail on the prep of the bullet (lubing).

FYI, I will be hand lubing with melted lube (beeswax n Moly Graph Lithium grease) in a pan, and for now I will be fire lapping a 44mag Ruger Redhawk, and a .357 Ruger Speed Six. Both of these revolvers are thread choked at the frame and leading begins here in as little as five shots fired, even using Hi-Tek coated bullets over #11 BHN bullets.

questions I have:
1. do you imbed the lapping compound onto bare bullets and then lube?
2. do you lube first and then embed the lapping compound?
3. or does it matter either way?

with #1 it seems I can be more thrifty with the lapping compound since I can wipe off the excess lapping compound and smear it back on the plate for the next bullets. Downside is contaminated left over lube would need to be tossed. I can probably save lube waste by lubing finer grit imbedded bullets first then working to courser grits. The backwards cross contamination of the lube should have little or no detrimental impact on firearm or lapping process.

with #2 I fear the process of wiping off excess lapping compound could cause the removal of some lube from the grooves.

[btroj]

I didn't lube or size.

Cast bullet pretty soft. Roll between two steel plates to embed the grit into the bands of the bullets. Load light, you only want bullets to exit the barrel. I mean light, like make sure you see each impact to verify the bullet left the barrel. Yes, that light.

Clean the chambers and barrel every 6 rounds, no need to scratch the chambers or try and lap leading in the bore.

Go slow, you can remove more but you can't put any back.

[Pilgrim]

Lapping compound is fairly cheap. Don't sweat the minor details. I lubed, rolled the grit into the boolit, and loaded them. IIRC on the order of 10 or 20 200 grit boolits removed the obstruction(s). Followed by twice as many for the next finer grit, then twice as many yet again for the next grit. IIRC I stopped at 400 or 600 grit. Don't go any finer than 600 grit. FWIW Pilgrim

[oley55]

[QUOTE=btroj;3046795]I didn't lube or size.

Cast bullet pretty soft. Roll between two steel plates to embed the grit into the bands of the bullets. Load light, you only want bullets to exit the barrel. I mean light, like make sure you see each impact to verify the bullet left the barrel. Yes, that light.

QUOTE]

The instructions from NECO warn/say too light a load is worse than too much. as not enough pressure to expand the bullet fully into the lands. So I plan to go with the minimum (starting load).

[oley55]

I remain concerned leading will start from almost immediately and subsequent imbedded rounds will be running over lead and doing nothing. I was hoping that my cleaning after each 6 rounds would be to remove powder residue and not gobs of lead.

yea, I'm probably over thinking this whole process.

[btroj]

That is why I don't size the bullets. I want the bullets just a bit larger than the bore at the largest dimension. A soft, like 40/1 type alloy is also a good idea- it gets sized down by the contraction and doesn't spring back out. Those soft alloys along with light charges of fast burning powder ensure the bore is sealed tight.

[tomme boy]

Wipe the bore with a oiled patch after each round or you will get leading.

[oley55]

Wipe the bore with a oiled patch after each round or you will get leading.

any particular gun oil? (Hoppes , LSA, CLP) how about krol?

[groundsclown]

+1 to what btroj said.
No lube or sizing
very light charge
clean after each cylinder full

I did this to my ss redhawk a while back using a beartooth lapping kit. Rugers SS is some of the hardest $&!T on the planet. I fired 120 rounds total over a weekend & I finally gave up. I still get leading right at the threads with light loads...so I bumped my charge a tad & all is fine now.

I used a rcbs 250-k & 3.8gr of w231 & shot at 5 yards, making sure each exited & hit the target.

[oley55]

+1 to what btroj said.
No lube or sizing
very light charge
clean after each cylinder full

I did this to my ss redhawk a while back using a beartooth lapping kit. Rugers SS is some of the hardest $&!T on the planet. I fired 120 rounds total over a weekend & I finally gave up. I still get leading right at the threads with light loads...so I bumped my charge a tad & all is fine now.

I used a rcbs 250-k & 3.8gr of w231 & shot at 5 yards, making sure each exited & hit the target.

yea, I've read that about the SS Redhawks. makes you wonder if you'll have a smooth bore before the choke goes away.

[oley55]

I wonder if using jacketed bullets would be better for the SS Redhawk

[btroj]

NO!

Jacketet bullets spring back after the constriction and smooth the bore but don't do as good a job at creating a slightly tapered bore.

A soft, really soft, bullet stays the size it is squeezed to after the constriction. This means it doesn't polish much after the constriction. A jacketed or hard alloy bullet springs back and polishes the entire bore but doesn't remove the constriction as well. We want to remove the tight spots and leave the rest of the bore alone.

My SRH took many rounds with 320 grit, probably 150 or so over a few years. It shoots great now. Between that and finding a bullet that fits better made it a great shooter than just doesn't lead.

[30hrrtt]

My super Redhawk had a terrible constriction at the threads. I fired more than a couple hundred rounds through it and it still had a very light constriction. They were all with the fine grit from Beartooth. Cleaned after each cylinder full. And no I didn't have a smooth barrel. That stainless is tough. When I did my stainless Redhawk, I sized the boolits so they just slipped through the cylinder before embedding the lapping compound. I also started with a courser lapping compound and finished with fine. It took WAY fewer shots to get it to even better condition than the Super Redhawk. Both shot jword's very well before but not so much cast without leading. Now they shoot anything very well. I did my new, made this year, 6" stainless GP100 the same way and very happy with the results.

[geargnasher]

+1 Btroj and 30hrrtt, not much I can add except there is no good reason I can think of to use starting loads for firelapping, 3 grains of Bullseye or something similar is a good place to start, try it with a normal, non-lapping load and the same bullets you intend to lap with before you start and see if they exit the barrel.

Gear

[DougGuy]

Your cylinder throats also need to be the size you want them to be, before lapping. It does a lot less good to fire lapping boolits through tight cylinder throats, and can bell mouth your cylinder throats as easy as it can lap the thread choke. This is actually the first step in firelapping, so your lapping boolits are not sized down. Should at least know their diameter in relation to bore size by now.

[oley55]

Your cylinder throats also need to be the size you want them to be, before lapping. It does a lot less good to fire lapping boolits through tight cylinder throats, and can bell mouth your cylinder throats as easy as it can lap the thread choke. This is actually the first step in firelapping, so your lapping boolits are not sized down. Should at least know their diameter in relation to bore size by now.

the Redhawk 44mag cylinders are definitely larger than barrel, so I'm good there. All six cylinders are 0.432" (using steel pin gauges). Slugging the barrel through the thread choke is 0.4300". slugged a third the way down the barrel an inch into the roll stamped markings and then backed the slug back out the muzzle and measured each pair of lands at: 0.4300", 0.4301", 0.4295".

Haven't slugged just the muzzle yet and still need to validate the cylinder's pin gauge measurement by slugging at least one cylinder.

For certain I can feel the restriction under the roll stamped markings and clearing the thread choke requires a couple good smacks with a hammer to get the slug to pass through.

[30hrrtt]

I would recommend sizing the boolits to .431 before embedding the lapping compound. Still larger than the barrel so will work on the constrictions but not so big as to overly wear the throats and decrease effectiveness of lapping. you will find that even sized a hair under, with your lapping compound on the boolit, it will take a gentle push to pass through the throat.

[oley55]

I would recommend sizing the boolits to .431 before embedding the lapping compound. Still larger than the barrel so will work on the constrictions but not so big as to overly wear the throats and decrease effectiveness of lapping. you will find that even sized a hair under, with your lapping compound on the boolit, it will take a gentle push to pass through the throat.

I am not yet invested in bullet casting. Accordingly, I do not have a bullet sizing press. I looked into getting a Lee bullet sizing kit, but they are not available in .431", (only .429 and .430). I'm not willing (or able) to buy a Lyman or RCBS press just now. Will have to wait to see what size the fire lapping slugs from Beartooth are.

I wonder if one can manually lap a lee die with some 1200 grit paper on a dowel rod.

[btroj]

Lee dies can easily be lapped. 1200 grit is a bt fine, I use 400 to get close then finish with 600.

search this site, I think it was Buckshot who posted instructions on how to do it.

[clintsfolly]

MyRedhawk was taking so many rounds that I got impatient and used a q-tip to paint the forcing cone with compound and used prepped bullet to carry it thru. Now it shoot great and never leads. Good Luck and have fun Clint

[oley55]

thanks, did a search and found this from Buckshot:

http://castboolits.gunloads.com/images/misc/quote_icon.png Originally Posted by bigted http://castboolits.gunloads.com/images/buttons/viewpost-right.png (http://castboolits.gunloads.com/showthread.php?p=1163820#post1163820) .....i want to explore the possibilitys of diff diameters with them as they apear to be a fairly easy item to resize with a reamer.
thanks
............You won't be happy with a reamed finish, trust me:grin: The actual sizing area in a Lee push through is less then 0.10" wide. Oiled carbide paper on a split dowel in a drill motor will get you where you want to go fairly quickly. That is unless you're wanting to take a .451" out to a .460". Then it'd be a career!

..............Buckshot

[wmitty]

Took a .285" Lee up to .301" for paper patching and yes; it did indeed take a while...

[geargnasher]

MyRedhawk was taking so many rounds that I got impatient and used a q-tip to paint the forcing cone with compound and used prepped bullet to carry it thru. Now it shoot great and never leads. Good Luck and have fun Clint

This works too, I have done it on two revolvers when I didn't want to affect the cylinder throats. I used dead-soft, lubricated slugs "breech seated" into the cylinder throats (flush with the front of the cylinder) and a VERY light charge of powder installed in the cases. The cases were unsized, just reprimed and charged, and were loaded in the gun with the muzzle up so no ring-causing filler or wads were required. Cylinder was removed and compound re-applied to the forcing cone area prior to each shot. Worked like a charm.

Gear

[oley55]

Based on discussions here, I decided to slug everything again with the following results:

cylinder throats which I had previously measured with pin gauges at .4320", actually slugged at: .4326-.4328".
full length, slug pushed out thru the breach: .4301"
barrel slug pushed into roll markings and then backed out thru muzzle: .4303"
muzzle about 1" into barrel then pushed back out: .4301"

I don't understand how I can get larger measurements from the middle of the barrel when that slug is either getting pushed back out the muzzle and all the way thru the breach (thread choke). the slugs are soft slugs from NECO so I doubt spring back could possibly account for this.

Regardless of that oddity, it seems the cylinder throats are a bit large and now question fire lapping at all.

Reading http://www.lasc.us/Fryxell_Book_Chapter_6_ThroatGroove.htm, quote: "The ideal cylinder mouth diameter is about one half a thousandth over the maximum groove diameter of the barrel. Sometimes it is impossible to achieve this magical combination since the cylinder mouths are occasionally larger than the groove diameter of the barrel. In this case the bullets will need to be sized the same diameter as the cylinder mouths. Extreme cases do exist where the cylinder mouth is as much as .005 larger than the barrel groove diameter. This is an extreme case, but it does happen occasionally. The only thing you can do here is to shoot exceptionally light loads and hard or gas-checked bullets, or resort to jacketed bullets."

I also question sizing bullets to the throat/mouth size as quoted above because my throats are very rough with obvious mill/ream marks. I can only imagine them immediately leading up. I really feel like they should be lapped n polished, but this would only make them even larger.

Unless I'm missing something, with the bullet floating/wallowing from case thru throat and forcing cone before reaching the barrel rifling this 1983 vintage Redhawk may be need to remain a jacketed bullet weapon only.

[DougGuy]

I don't think you will hurt it by firelapping. Nor do I think the throat sizes are an issue. They are just about right for sizing to .432" which many do, myself included. I think you will still have a noticeable improvement by firelapping the choke out. It certainly isn't going to hurt it by proceeding.