260 Remington, Cast, 45 2.1's Help

[StarMetal]

Fellows most of you know that I built a 260 Remington on a Type 38 Jap Arisaka action. You also know it shoots jacketed very well, but I had been having the devil of a time getting it to shoot cast. I just about gave up on it, until 45 2.1 got involved. We started out arguing and have ended up being good friends. It's not easy for a "know it all" ME, to admit that someone else figured it out, but they did and that someone else was Bob. Bob sent me some of his bullets that he casted and has been coaching me along unknowningly to you all through private messages. Well today it paid off. I got the 260 shooting his cast bullet which is a discontinued Lyman design weighing alittle over 120 grs. I got the thing going 2200 fps out of my 9 twist barrel. The load is 29 grs of surplus 4895, Remington brass, Winchester large rifle primer, and a tuff of Dacron. Althougth the loads don't lead the barrel what-so-ever it fouls the bore. My 260 seems to be like a 17 caliber rifle where it needs to be cleaned more often. You can see on the target the groups on the top and the bottom which are marker pen marked what was going on. The group that finally paid off is the vertical one right below the bullseyes which I marked with an arrow. Imagine now that 2200 fps and those are 6.5 cal holes, so even though I strung the group it's still pretty small. I'm satisfied with it. Bob thanks a million. Bob knows his stuff. Carpetman, I apologize for not shooting a ragged hole.

Joe

http://www.hunt101.com/img/292728.jpg

[carpetman]

Starmetal----Joe you don't have to apologize that it was not a one hole group you posted. It was a freshly shot group and hasn't had time to cure yet. Sprinkle some keyboard seasoning on it and give it a week. It will be a one holer. Give it two weeks and it will be one holer only all day long.

[slughammer]

...figured it out,
You can see on the target the groups on the top and the bottom which are marker pen marked what was going on.
Bob knows his stuff.

Nope, can't see what was going on. What wuz going on?

Is the load data the secret, or was there more going on? Can ya tell us which particular things made the difference?

Inquiring minds want to know.

[StarMetal]

Well the groups on the top as you noticed, looked like a shotgun did them. The secret was the right amount of the powder and the neck tension on my brass. I was starting to get good groups, but with too many flyers. I knew it wasn't bedding because I sorted that out with jacketed bullets when I first got the rifle together. By the way it was free floated first and didn't hold the groups, so then I made a pressure point up near the end of the forestock. I notices when sized the brass and then putting the bullets in them that the neck tensions weren't all the same. I told Bob this and he said that could very well be what's causing the flyers. Then I got out of my new unfired brass and tried again. That was today. That was it. Along with this is the excellent bullet that Bob sent me. Not only were they cast well, it's a good design. I may go back now and try some of the bullets that failed on me.

Joe

[slughammer]

How is the fit of boolit to throat?

And loaded round to the neck of the chamber?

(As a boolit caster, I don't want to hear that NEW BRA$$ was the answer, got to keep searching or I won't be able to sleep...)

[StarMetal]

New brass was the answer only in that it had more consistant neck tensions then the cases that had been fired alot. That in conjunction with the right amount of powder and proper bullet sizing and fit to the throat. The freebore and long throat on my rifle is .2659. The groove diameter is dead on .264. Right were the freebore tapers it's .265. So I size my bullets to .265. The rifle won't chamber a .268 bullets. The taper part of the leade in touched the nose of my bulletc about 1/2 way down the ogive. So it's all those things together. The necks on the Remington brass for the 260 isn't very long, about like it is on a 243 and on my brass it's not very tight, even if I take the expander plug out of my RCBS dies the necks of the fired alot brass won't hold the bullet real tight. I'm thinking that this lot of brass I have is thin.

Joe

[Scrounger]

New brass was the answer only in that it had more consistant neck tensions then the cases that had been fired alot. That in conjunction with the right amount of powder and proper bullet sizing and fit to the throat. The freebore and long throat on my rifle is .2659. The groove diameter is dead on .264. Right were the freebore tapers it's .265. So I size my bullets to .265. The rifle won't chamber a .268 bullets. The taper part of the leade in touched the nose of my bulletc about 1/2 way down the ogive. So it's all those things together. The necks on the Remington brass for the 260 isn't very long, about like it is on a 243 and on my brass it's not very tight, even if I take the expander plug out of my RCBS dies the necks of the fired alot brass won't hold the bullet real tight. I'm thinking that this lot of brass I have is thin.

Joe

Joe, I used to shoot the 7/08 Remington a lot in Silhouette competition. It was thought by a lot of us that better accuracy was achieved by necking down .308 brass than by using factory 7/08 Remington brass. You ended up with a thicker neck which seemed to fill the chamber better. The brass of choice was LC Match. You might give that a try.

[Bass Ackward]

My 260 seems to be like a 17 caliber rifle where it needs to be cleaned more often.
Joe

Joe,

Does this surprise you? Fouling sizes down a bullet and is worse with cast. The faster the bullet goes, the greater the effect. The faster the twist, the more stress on what still makes contact.

So the faster twist causes a bullet to lose contact sooner than a slow twist and strip. Or .... you need taller rifling with a faster twist. Or .... you need taller rifling for higher velocities. Or a longer bearing area and less rider for strength. Or a harder bullet.

But what really kills with a fast twist is that it retards forward motion more too. Which increases the effect of inertia and causes more pressure on the base. So one of the most egregous of errors for cast, in this case, is to increase bullet weight with a faster twist. In fact, you want to do exactly the opposite if you want high velocity. What you have to have is a short enough throat to do this.

All of these things work against the golden rule for cast which is to start a bullet off as easy as possible for the best accuracy at the highest possible velocity.

So any action you can take after getting good ignition that allows the bullet to start moving sooner and delays peek pressure until the bullet is moving as fast as possible is the same as increasing bullet strength. That is one reason why I go smaller in bullet diameter the faster I want to go.

As a side note, watch out for Bob. He'll have you crimping before long. :grin: The 45 2.1 is a dead give away.

[StarMetal]

Bass

It surprised me in the fact that it fouls in so few shots. Ten to be exact. The bullets are oven hardened. The bore is really good looking after shooting. In all the shooting I've done this last time never were there any slivers or traces of lead on my patches. I also tried different lubes to see if that was it and it wasn't. I guess it's just a build of of powder residue, lube, and microscopic lead particles, but it builds fast in this bore. I don't see it as bad in any of my 22 caliber rifles and their bores are smaller the rifling as shallow or even more so.

Joe

[StarMetal]

Art

I was just discussing that with someone over the phone. I was thinking of sizing down some 308 winchester brass or sizing up some 243 winchester brass. I'm not real fond of remington brass. I'll probably size down 308 brass.

Thanks
Joe

[45 2.1]

All of these things work against the golden rule for cast which is to start a bullet off as easy as possible for the best accuracy at the highest possible velocity.
As a side note, watch out for Bob. He'll have you crimping before long. :grin: The 45 2.1 is a dead give away.

Bass-
The Golden Rule for cast is to get the bullet into the bore straight and made of an alloy suitable to the pressure desired. And as a matter of FACT, crimping does help in alot of calibers when trying to achieve suitable ignition pressure. The 45 2.1 is not a giveaway, most all of the blackpowder guys do not crimp.

[imashooter2]

Art

I was just discussing that with someone over the phone. I was thinking of sizing down some 308 winchester brass or sizing up some 243 winchester brass. I'm not real fond of remington brass. I'll probably size down 308 brass.

Thanks
Joe

Have you slugged your chamber to see how thick a case neck you can use?

[StarMetal]

Yes I have slugged my chamber and know how thick a caseneck it will take.

Joe

[Bass Ackward]

I don't see it as bad in any of my 22 caliber rifles and their bores are smaller the rifling as shallow or even more so. Joe

Joe,

You won't notice it as much in a 22 unless you were pushing the envelope. What puts more stress on a lead bullet, .003 rifling gripping into a 55 grain, .224 diameter bullet with a 7 twist or .004 tall rifling trying to turn over and grip a 350 grain, .458 slug in a 14 twist? So shooting a "fast" twist is not just a low number, but also a relative to bore size. And cold weather fouling plays hell with larger bores for this very reason.

Bob,

Yep. Them black powder boys have inspired me, because now I am not crimping with smokeless in a 45 either these days. Always a new challenge. Rules .... are made to be broken.

[Buckshot]

.........Joe, if you check on the "Group Buys" forum on the 6.5mm Kurz Group Buy, you'll see a photo of the Lyman HP design 45 2.1 supplied to you. The group buy design was to mimic the Lyman as far as possible, naturally sans HP.

Before I sold the mould I cast up about 100 of them and used visually inspected ones to run the velocity check I'd previously posted about. I shot 10 shot groups at 50 yards (iron sights M96 Swede) and the last groups were up over 2,000 fps. Final group, highest velocity was 1.4" for 10 rounds. Nice round group.

In fact, to complete the test I had to go back and re-evaluate some of the rejected boolits and use a few of'em. It's hoped that this most recent 6.5 mm custom mould run will produce a boolit capable of reaching, if not exceeding 2,000 fps with good useable and CONSISTANT accuracy.

In any event, good work between you and 45 2.1 and your success with the 260 Rem.

Several years ago I did a 40 round test for something to do. The rifle was a 1-6.48 marked M38 Swede in like new condition. The test consisted of 2 variables in 4 loadings. Crimping/no crimp and sizing at .264" and .266". At this time the rifle had a Tasco 4X scope in a scout mount and the groups were fired at 100 yards, 10 rounds each.

There was 10 each sized .264" crimp and no crimp. Ditto sized .268". The rifle turned in a definately better performance with the boolits sized .264" and crimped. Second best was also those sized .268" and crimped. The powder was 34.0grs of WC872 so the crimp may have helped in a bit more consistant combustion, since both crimped loads came in 1 & 2. I now regularly crimp my 6.5mm cast loads.

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

[Bass Ackward]

I now regularly crimp my 6.5mm cast loads.

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

Yep,

And there in lies the negative to a light cast bullet, high velocity cast load. That was what I was trying to tell Joe in a tactful way. Because I can imagine .... Bob mentioned it to him. If you can see improvement using new cases, then crimp will help out. You can only go so far with neck tension, or thick cases, before you start unwanted sizing. Especially, if you want to stay soft.

The good group he shot was either ignition or the tip pressure on his rifle is too heavy. Since I assume Joe would have considered bedding long before these trials, .... then the light crimp might help out. Especially if he is seeing this in the 4895 burn rate range.

Many people don't even consider crimp with a bottle necked case and instead think of simply using filler. While I personally shy away from fillers and increase powder charges to improve ignition, sometimes I can't because of leading.... so I have to crimp. Or try both crimp and filler, even if it means dropping the charge.

But Joe is getting close for THAT load. Now he needs 9 more so he can pick the best one. :grin:

[45 2.1]

Yep. Them black powder boys have inspired me, because now I am not crimping with smokeless in a 45 either these days. Always a new challenge. Rules .... are made to be broken.

Bass-
Some rules are solid, break them and you will have gone down a wide path to failure like so many others.


And cold weather fouling plays hell with larger bores for this very reason.

Your bullet, lube and powder choice have more effect here then temperature do.

[Bass Ackward]

Bass-
Some rules are solid, break them and you will have gone down a wide path to failure like so many others.

And cold weather fouling plays hell with larger bores for this very reason.

Your bullet, lube and powder choice have more effect here then temperature do.

Bob,

True. To a degree maybe. But how do we learn if we don't go where no man has successfully gone before? Because when satisfaction is found, learning stops. I mean bullet, powder and lube are the game aren't they?

But my experience is totally different. All of my 1/2" loads in summer can not be adjusted to shoot that way in the cold with a big bore. About 1 1/4" is a great day and all I can do in the cold. And much larger groups are more the norm. Now understand I am not talking about burning three in the dirt here to warm the barrel and then shooting for group while the barrels hot. That will still shoot 1/2". I am talking about shooting cold groups as if hunting. Trying to get reliable accuracy for the cold.

I have tried virtually every lube and every combination of lube out there. Quantities of lube, etc. Plain and simple .... fouling get's stiffer in the cold and causes more sizing. Forcing velocity reduction. For me, this effect is more pronounced or proportional per increase in bore diameter.

While my cold weather designed bullet does do a better job of handling fouling, shooting .... much more consistent in the cold than traditional olgival designs, it too shoots dramatically better in the warm. So nothing I have found to date over comes cold to perform as well as when warm.

Oh, some variables make make more difference than others, but in the end .... nothing works magic like warm weather.

[45 2.1]

I have tried virtually every lube and every combination of lube out there. Quantities of lube, etc. Plain and simple .... fouling get's stiffer in the cold and causes more sizing. Forcing velocity reduction. For me, this effect is more pronounced or proportional per increase in bore diameter.

While my cold weather designed bullet does do a better job of handling fouling, shooting .... much more consistent in the cold than traditional olgival designs, it too shoots dramatically better in the warm. So nothing I have found to date over comes cold to perform as well as when warm.

Oh, some variables make make more difference than others, but in the end .... nothing works magic like warm weather.

Bass-
You have a very long way to go yet. When you find that what you have stated above is not necessarily true, you will be on your way to finding what does work all the time. Good Luck in your search.

[Bass Ackward]

Bass-
You have a very long way to go yet. When you find that what you have stated above is not necessarily true, you will be on your way to finding what does work all the time. Good Luck in your search.


Bob,

Thanks! After I eventually get to where you are with 45s, I intend to go after the Hornet mystery. Please don't tell me if you have that one figured out too. That should hold me until I check out.