Adventures with NOE 246-105-FN

[Stonecrusher]

This mold was a Christmas gift from my wife. I think it was so she could shoot her hunting rifle a lot! She has an A-Bolt Micro Hunter in .243 Winchester. I have a Remington 700 in this caliber so I set out hoping to find a load that would shoot good enough out of both rifles to keep things simple. To start with the throat in my 700 is .06" longer than the A-Bolt so I would have to reset the seating die each time. I was inspired by JWfilips' posts about this bullet so I thought I would ride his coattails to a good load. I spent some time to be sure all copper was cleaned from the bores before beginning.

The consensus seemed to be that this design likes a little speed to shoot its best so I copied his load almost exactly except my bullets were air cooled instead of water dropped. I have used this alloy up to 2,200fps in 30-06 and 2,900fps in .222 using Ben's Red and got no leading so I felt pretty safe at around 2,000fps.

The load was:
NOE 246-105-FN sized to .2465" lubed with Ben's Red and a topcoat of BLL.
Alloy was COWW with 2% tin
RP cases 20.0 gr RL-7 and WLR primer
OAL was 2.760" for A-Bolt and 2.820" for the 700. First band engraved about .015" in both rifles and the nose engraved slightly in the A-Bolt but not the 700.

All shooting was at 100yds. Forgot my chrono that day but I am guessing about 2,000fps. First shot from both rifles were a little low as I suspected. Couple of adjustments and I was close enough to begin.


I then put the last three into a group from the 700, not bad for 1st try,


Group from A-Bolt was about the same, but the target was pretty much wiped out from a bullet striking the target frame. So I fired a five shot group from each rifle. Yikes!!!



I couldn't really see any appreciable leading in the bore, but something wasn't right. The last five rounds from each rifle was a complete disaster. Only two shots from each even hit the 28" target backer. When I got home I pushed a patch through each rifle. I have never leaded up a rifle barrel before, but on this day I accomplished it twice! Took a while to get it all cleaned up and I didn't enjoy it.

I noticed that there was no lube star of any kind on the muzzle so I thought for my next try I would slow it down some. There is an article on 6mm in "The Art of Bullet Casting" and the author said he was getting his best accuracy using 15.0gr of RL-7 at about 1,600fps. My next attempt kept everything the same as before except for the powder charge of 15.0gr versus 20.0gr.
Sighters:




Looking a little better, except it seems like the adjustment on my 700's Simmons Pro50 is a little sticky and had to drift to the adjustment. I had sixteen rounds for the 700 versus fifteen for the A-Bolt, that's why there are six rounds on the sighter target.
Then I fired two groups of five shots each. Top one is Rem 700 and bottom is A-Bolt:




Not too bad. Two groups aren't the last word but it is very promising. Groups kept getting better and I think the bore was just getting seasoned to the lube by the last five shots. There was a very, very slight lube star on both muzzles and zero leading this time. I did bring my chrono and rifles were almost identical with 1615fps from the 700's 22" barrel and 1614fps from the A-Bolt's 20".

I can't wait to try it again! I did heat treat some bullets for the next go round and got about 23BHN versus about 13BHN when air cooled.

I am wondering if this design may not carry as much lube as it should. The volume of the grease grooves is less than the NOE 225-55-FN(RCBS) and the bore surface is of course greater. With the .222 I get a nice lube star using Ben's Red. Just goes to show each barrel acts different.

Will update after next range trip, probably Thursday.

 

[Maven]

"I am wondering if this design may not carry as much lube as it should."

sc, I sometimes wipe a coat of Lee Liquid Alox on bore riding noses to preclude bore leading. It's a tad messy and time consuming, but it does what it's supposed to. Now a question for you: Why are you heat treating @ <1,700fps? Btw, I've occasionally run my .243Win. (Ruger #1 + Lyman 245496 @ .244") at 1.900fps with nary a hint of bore leading with CB's that aren't heat treated.

 

[Stonecrusher]

Maven, I have only tried heat treating once before and I hosed it up. Everything else I shoot is air cooled. There is no real reason other than others were running faster with water dropped and I thought it may tighten the groups a little by stopping a flier here and there. Bullets were culled and weight seperated so I thought the fliers may be coming from damage when bullet entered rifling. Also thought I might be able to set the OAL the same for both with decent accuracy. The one benefit would be going from 15"-16" drop at 200 yards to 8"-9" if zeroed at 100yds.

Like I said, no real reason just messing around. I am using BLL as a top coat for the same reasons you stated.

 

[Maven]

I used to weigh and heat-treat my CB's as well, but no longer do the latter as our current oven doesn't heat evenly enough for HT. However, I rarely get more than a trace of bore leading and thus find I can live without it. As for weighing CB's, only on rare occasions and tend to agree with CBA president John Alexander, that it's much effort for little reward. Btw, Jon has a good article in the Jan. - Feb. 2016 "Fouling Shot" about CB myths. He calls it "Our Zombie Problem" and it's well worth reading.

 

[KHornet]

Have had a number of 243, none of which shot the long heavy bullets due to twist. However 85-90 grainers shoot very well.

 

[JWFilips]

It took me awhile to get that bullet to shoot well. Found out it needs close to 2000Fps And a bit of harder alloy
20.5 grain Reloder 7 and 16 grains 2400 are proved good loads Ben's Red with a BLL overcoat Shot out of my 1980's Ruger 77 V 243 Win @ 50 yds

Then some days you get real lucky Like Just Blowing out full length sized cases ( 15 shots)

 

[Stonecrusher]

JWfilips, like I said in my original post I was trying to copy your results. 20.0gr of RL-7 leaded the pure mortal crap out of the barrels. When I dropped back to 15.0gr, I got the last groups at 100 yards. No leading the second go round. I did heat some to try this week sometime. They came out about 23BHN. Hoping this might help with eliminating fliers. I would like to get the velocity up to around 2,000 fps to shoot a little flatter for real world situations. It doesn't really matter for poking holes in paper.

What kind of lube star are you getting? With 20.0gr there was nothing for me. At 15.0gr there is a very slight smear, you almost have to wipe with a towel to see it. I was thinking that the bullet could carry a little more lube and be happier.

 

[JWFilips]

Stone crusher, I think you will see a difference now with that harder alloy. I shoot a 50 % pure/ 50% COWW and add'l 2% tin Oven hardening let me shoot them at a speed that got them to fly accurately with zero leading ( I have also water dropped ) both come in at about bhn23. I usually have a rather light lube star Yes an add'l lube groove would have been better & I wish the nose was flat instead of pointed.

When I was getting leading early on I could never get the rifle to settle down ( because I had to clean it each range trip) Once I went to the harder bullets I didn't need to clean the rifle bore so it only took two range trips to get it so settle in. Right now I have about 500 rounds through it and my first round I shoot is very predictable. The most cleaning I have done to it is to wipe the chamber with a dry cotton mop after each range trip and after a few range trips push a dry patch through the bore. The Ben's Red seems to leave just enough lube deposit that the dry patch moves very smoothly down the bore.

Looking at your starting groups and you progression I would have to say I followed that same road. I think you are going to be very close this next time out.
Not sure if you sort your bullets by weight but it is a good idea I sort by .1 grain Like you I load long I never crimp or remove the case neck bell
I'm neck sizing in a Lee neck size die with a larger custom mandril (.244" dia) Now I'm strictly sizing .246" My rifle prefers that size the best

Also keep in mind I shoot at 50 yards

looking forward to seeing your new tests
Jim

 

[Stonecrusher]

Jim, thanks for the support. I am weight sorting. After my last casting session of about 150 I had two groups within .4gr and only six about outside the range. I do sort my .22's to .1gr though. So, these groups were fired with bullets +/- .1gr. Your experiences with Ben's Red are just like mine. This is the first time i have ever experienced leading when using it. Usually have good lube coat in the bore but my other molds hold more lube.

Good to know you got leading with the softer alloy too. Maybe the heat treat will allow me to get back up in speed. If not, I will be happy at 1600fps.

I am using a Lee collet sizer as well. For my M-die I turned down a .257 plug to .245" for about .0015" neck tension and set the sizer so it just stops the plug from entering. Works the neck less. I don't crimp either.

I thought at first the .2465" diameter might be causing the leading in the A-Bolt because the entrance to the throat is just a little over .244, but the 700 is larger and it was doing the same thing. I have lapped out my Lyman die to size .2465" but made a push thru at .245 just in case. My 700 has been shot a lot more having been made in 1976 and has over 1000 jacketed throught it. My wife's A-Bolt has only had about 350 rounds of jacketed through it.

Hopefully will have a good range day Thursday.

 

[Ian]

You can shoot those softer bullets fast but you'll need a MUCH slower powder than Reloder 7.

Also, you don't need that 2% extra tin for what you're doing, in fact that's probably part of your leading issue. Tin doesn't play nice when scraped hard against the sides of the lands, it likes to stick and rub off in the bore so your engraves widen and you lose the gas seal due to blow-by....which is also where your lube star went. You ran out of lube all right, but not exactly in the way you might be thinking.

I'll bet you have much better luck with the hardened bullets, look forward to seeing it come together.

 

[KHornet]

I tend to strongly agree with Ian!

 

[JWFilips]

Ian,
Thanks for your observation & tip. I started adding that 2% extra tin a few years ago when I was casting for one of my 357 Mag pistols It seemed I was getting a better mould fill out with the bullet I shot in it and from then on it just became a habit and that became my regular alloy Now that I'm only shooting rifles , with your observation I will leave the extra tin out on my next batch. I just love the way your mind works …This is truly a place to learn the Art & Science of the cast bullet!

 

[Stonecrusher]

You can shoot those softer bullets fast but you'll need a MUCH slower powder than Reloder 7.

Also, you don't need that 2% extra tin for what you're doing, in fact that's probably part of your leading issue. Tin doesn't play nice when scraped hard against the sides of the lands, it likes to stick and rub off in the bore so your engraves widen and you lose the gas seal due to blow-by....which is also where your lube star went. You ran out of lube all right, but not exactly in the way you might be thinking.

I'll bet you have much better luck with the hardened bullets, look forward to seeing it come together.

This is my first time out with RL-7. I understand about the slower powders. I am using IMR-4064 and Varget in.222 Rem and getting good velocity, 2400-2900, with the same alloy. I am usually not a velocity hound but 2,000 seemed doable. I guess I was mistaken!

Could you explain more about the tin causing leading? I have heard about high antimony alloys causing something similar but not tin. COWW with 2% tin is my usual alloy and have even gone to 2,200 in 30-06 with no leading, but with a slower powder. The leading present was just like that from gas cutting so what you are saying makes sense, I have just never had it happen before with good bullet fit.

I have been casting for rifle since 1990 but until two or three years ago I only owned one mold, a 31141. Most of experience has been with the various .30 cals, and several other molds and I never tried to push for velocity being more concerned with accuracy. When I started casting for .22 last year the velocity went up easily but the bullets took considerably more care. Things change rapidly when velocity goes up and bore size goes down.

The velocity isn't that important to me, I am curious as to why it happened though.

 

[Rick]

You can shoot those softer bullets fast but you'll need a MUCH slower powder than Reloder 7.

Also, you don't need that 2% extra tin for what you're doing, in fact that's probably part of your leading issue. Tin doesn't play nice when scraped hard against the sides of the lands, it likes to stick and rub off in the bore so your engraves widen and you lose the gas seal due to blow-by....which is also where your lube star went. You ran out of lube all right, but not exactly in the way you might be thinking.

I'll bet you have much better luck with the hardened bullets, look forward to seeing it come together.

I can't completely agree with that. I don't/haven't shot fast powder at low velocity in rifles so won't speak to that but . . . I use 2% Sn in ALL of my alloy's from 8 BHN in 1911's through magnum handguns & rifles at 12-18 BHN to 2,000 fps and I get no leading, no rubbing off, no running out of lube. I don't see Sn as evil as some seem to, I see it as a benefit in castability and malleability on target. Different folks, different shooting, different firearms, different results.

I use 2% Sn with no issues. I used 3% Sn for some time in all alloys/guns simply to test for positive/negative results. The only difference I could note was that my Sn supply went away faster so I went back to 2%. Too much Sn could certainly be used but I've never been able to notice any negative effects from 2% or 3% Sn.

 

[Stonecrusher]

Rick, Almost all of my rifle experience has been below 1,800fps with fast powders such as 2400, IMR-4198 and now RL-7. I am starting to like RL-7. It meters very well and doesn't seem position sensitive in .243. The extreme spreads are very low without filler. I get much more variation with 4198 unless I use a little dacron.

I also try to get about 2% tin my alloys and have never had a problem. I am curious about Ian's statement on tin. I always try to learn from everyone. If anything strange is going to happen that no one has ever seen, it will be to me!

 

[Rick]

Will have to have Ian explain it. I have seen him post that before and have tried mightily to figure it out. All I can say is that his results have been different than mine so he has something in mind.

Not only haven't I shot rifle at very low velocity with very fast powders but I haven't delved into high velocity with rifles either. If there is a difference there with Sn I can't say, will have to hear what those that have say about that. For all of my shooting 2% Sn has worked very well. The majority of my casting, loading, experimenting has been with heavy for caliber bullets with the slowest powder that will get me to the desired velocity, a game plan that has served me well.

 

[Ian]

Ok, Rick, Lemme 'splain. First off your pistols have slow twists, are large caliber, and aren't going all that fast compared to rifles. No surprise you have never witnessed what I'm talking about. When you get above somewhere about 2,000 to 2300 fps you'll start to see how tin is your enemy. Remember Molly's thread on CB about "If you think so, try this"? He wrote about velocity limits with rifles and never could get his head wrapped around what people were telling him later in that thread....which is what I'm telling you and Stonecrusher now: Rifling wants to eat away at the bullet at high velocity/high acceleration. The lands will cut the engraves wider unless you have an alloy that is compatible with not only the velocity/acceleration rate, but the barrel steel and finish as well. Lube plays a part, too, as does peak pressure and pressure curve.

High-tin alloy, for whatever reason, is very susceptible to HV land erosion. I don't have a scientific explanation, just observations about different alloys and what they do when pushed hard in rifles. Linotype is another one famous for failing at HV. That one is easy, the "unbound" antimony dendrites that form near the surface of the bullet are brittle and fragile like glass dust or carborundum grit and easily crush and wear away in the bore. What I have found (a party of one) is that too much of either antimony or tin, regardless of proportion to each other, makes an alloy that doesn't resist erosion from the lands very well. Yes, linotype is very slippery and seems to glide on barrel steel quite well....but it doesn't hold up physically past a certain limit which is easily reached in rifles in the mid-velocity range. 2% tin plus whatever is in the WW to begin with is too much for shooting fast with a fast rifle powder in a small bore gun, particularly IF THE BULLETS HAVEN'T BEEN HEAT HARDENED AND AGED. Just trust me on that one.

IF the bullets have been heat treated for hardness, the WW %2% tin alloy can handle a lot more acceleration before the bullet metal starts sloughing off on the leading edge of the lands.

If the bullet metal starts to slough off and leave gas gaps, you get the typical "undersized bullet" type of leading all the way down the barrel (or at least the last half toward the muzzle end), a dry muzzle, and poor accuracy.

If the powder used peaks pressure too soon and drops below the bullet's elasticity point midway down the bore, the bullet will relax right at the moment it is needing maximum seal (as the lands are really starting to whiz along the engraves), and you get widened engraves, gas leaks, gas cutting, think you ran of lube and need more grooves, etc. etc.). Lowering velocity, slowing powder, and toughening the bullet through heat (not alloying it up) are ways to work at higher velocity with faster powders to keep that all-important obturation of the bore intact. Lube has to not be too thin at the relax point, too, and that's where the metal soaps really earn their place in lube formulations.

This is a SYSTEM. You have a window in which to work. If you go outside that window things fail. The window is a range of alloy, a range of bullet temper/hardness, and a range of powder pressure curves that will work for a given muzzle velocity.

I can't say this enough: POWDER AND ALLOY. POWDER AND ALLOY. POWDER AND ALLOY. You have to match the hatch or it ain't gonna work. Most people never, ever realize how critically important those things are because they escape the effects of a multitude of reloading sins through the blissful ignorance and tremendous margin for error facilitated by sticking to low to medium-velocity cast bullet loading data for their rifles. Most reloaders don't understand the importance of neck tension to revolver accuracy, either, because it doesn't matter much if they're just shooting steel at 15 yards with a .38 Special. If that sort of casual loader/plinker gets into IHMSA he's going to have to get his stuff together to build loads that hit. It's the same sort of learning curve when you step up from medium to high velocity in a rifle.

 

[Stonecrusher]

Ian, that is a very clear explanation. Makes sense to me and is not something I have had happen before so it was a poser. I usually try to keep things simple and just want to shoot economically. I never thought about the difference between alloying up and using heat treat.

I have pushed the NOE 225-55-FN to almost 2,100fps using 8.0gr Unique without leading. Based on what you are saying I assume the lesser mass of that bullet is keeping this phenomenon from happening in that situation.

I think I will heat treat some more bullets and try pushing the velocity back up. I only heat treated thirty for this round of testing. If it works then I have learned another valuable lesson. For poking holes in paper I may continue to use the lower velocity and air cooled alloy to make life a little easier. It is good to have options.

Thanks for your detailed explanation on this! The level of knowledge on here and CB always astounds me. That is why I read much more than I post.

 

[JWFilips]

Stonecrusher,
Keep us posted with an update on this! Ian good explanation.
Thanks
Jim

 

[Stonecrusher]

I will keep you posted. Even with the leading I am enjoying this. Over all it has been easier to get the accuracy out of the .243 than the .222....so far.