Mixed Boolits - water dropped and air cooled.

[BrianL]

I just had two lots of 7mm Soupcan bullets sized and lubed. One was air cooled and the other water dropped. There was a noticeable difference when sizing and lubing . Long story short, my helper didn't know of the difference and boxed them together. From your experience, what can I expect for grouping when fired for accuracy. The pistol is a TC 14" 7-30 waters @ about 1900-2000 fps.

[tazman]

Depending on the alloy and how long it has been since they were cast, you could do a scratch test with your fingernail or an appropriate hardness pencil and find out which are which.
Sorry, but I have no idea what grouping will do.

[btroj]

Could be a problem depending on the alloy. Accuracy may well suffer.

[BrianL]

Sorry, I should have mentioned that the alloy was straight COWW with no added alloys. It was 30 year old ww at that. Would the hardness alone affect the accuracy? The finished weights are identical as well.
I meant to say what differences can be expected from mixing them, not "what can I expect for accuracy"

[rintinglen]

How accurate is the load to begin with? How well can you shoot that gun? Yes, the hardness will affect accuracy. Whether it will affect it enough to matter is another issue, but I suspect that at that velocity the air-cooled will be leading. And that will affect accuracy.

[btroj]

Yeah, hardness could affect the accuracy. Not a good thing. How much is hard to say but I bet you are gonna find out.

[scottfire1957]

Harden that entire lot, then cast some to air cool. Or, split the lot in half, harden one half, then remelt and recast and air cool the second half.

You could also remelt the entire batch and start over, giving proper instructions to your helper.

Or, you could test the BHN of each projectile and separate them and proceed as planned beforehand.

So many options.

[scottfire1957]

Load 'em and shoot 'em. Tell us if there is anything notable.

[HARRYMPOPE]

Load 'em and shoot 'em. Tell us if there is anything notable.

Thats what I think also.

[Shiloh]

How accurate is the load to begin with? How well can you shoot that gun? Yes, the hardness will affect accuracy. Whether it will affect it enough to matter is another issue, but I suspect that at that velocity the air-cooled will be leading. And that will affect accuracy.

Bingo.

Shiloh

[masscaster]

Since they're the same Alloy, same Size, same Lube, same Load, they'll all shoot the Same.

[RobS]

Since they're the same Alloy, same Size, same Lube, same Load, they'll all shoot the Same.


I just had two lots of 7mm Soupcan bullets sized and lubed. One was air cooled and the other water dropped. There was a noticeable difference when sizing and lubing . Long story short, my helper didn't know of the difference and boxed them together. From your experience, what can I expect for grouping when fired for accuracy. The pistol is a TC 14" 7-30 waters @ about 1900-2000 fps.


Now the rounds may all shoot the same depending on the firearm and demands placed on the boolits. However the boolits are not the same in that one set of boolits are much harder than the other. I would imagine there will be a bit of difference but don't know enough about the twist rate, lube used, brass prep, seating depth, powder, among a few other variables.

[Djones]

If it ends up being a problem, you could oven heat treat the batch. This would save the as cast boolits but would require re-lubing them.

[garandsrus]

It will be an interesting experiment! Shoot a group of 20 or so and see if there is a difference in POI.

[geargnasher]

The hard ones will make one group, the softer ones another. Hardness affects the pressure curve somewhat. One group might be considerably smaller than the other depending on which temper the load and gun happen to like better.

Gear

[MtGun44]

What gear said is correct, but I would be interested in seeing how much
difference there will be. May be very small. I agree that you need at
least one single 20 round group to sort this out, and at least at 100 yds.
If the difference is significant, there will be two groups. If very small it
will be one oblong group.

Please report back. I use AC WWt for all my rifle shooting, but it is miniscule
compared to pistol shooting, so I am no kind of an expert on the rifle end
of things.
I am thinking there may be very little difference if the load is mild and more
if the load is hot.

[BrianL]

The test gun will be a scoped TC Contender Super 14" in 7-30 Waters, 1-9" twist. It shot the Lee 135's into a nice cloverleaf at 25 yds with the factory open sights and fire forming loads with new Winchester 30-30 brass. I will add the scope this weekend.
For best results, what would you all recommend for speed? I have a pretty good selection of powders on hand.

[Dusty Bannister]

It would be a good idea to test the mixed bullets to see if the two groups do form. Then if necessary, wash off the lube, divide into two groups. HT and quench one group. HT and allow to air cool the second group. That would put you back to the beginning. Testing would be the first step whichever plan you choose to follow. Dusty

[gwpercle]

Sizing a water dropped boolit works the surface and softens it . the sized portions will now be just about the same hardness as the air cooled ones.
The proper way to harden a boolit is to first size, then heat, then water quench. Pan lube or use a method that doesn't work the hardened surface. Now you got a hardened boolit.

[cbrick]

Wow, what an assortment of answers.

First, I shoot air cooled CWW in several rifles to 2000 fps and no, it doesn't lead and doesn't need to be harder. Depending on your velocity the 1/9 twist may work better with the harder bullets by taking the rifling better.

Mixed BHN within a single group is something I have tested and yes, it will open up groups. How much will depend on pressure/velocity and range fired at. The harder you push them the more difference there will be. The longer the range the easier it is to see the groups open up. I tested this at 150 meters with a known load that grouped well, with the groups fired with mixed BHN there were no groups, couldn't hardly keep the rounds on the target.

It is impossible to surface harden lead, once quenched the bullets will be the same hardness through and through. You can case harden steel and it will be a surface hardness but not so with lead.

Rick

[leeggen]

I'm with Dusty, I would divid into 2 groups and heat treat and quinch one group and heat treat air cool and be back at the beginning where you wanted to be.
CD

[RobS]

Sizing a water dropped boolit works the surface and softens it . the sized portions will now be just about the same hardness as the air cooled ones.
The proper way to harden a boolit is to first size, then heat, then water quench. Pan lube or use a method that doesn't work the hardened surface. Now you got a hardened boolit.

Have you actually sized a water quenched boolit down to varify that you are taking a 20+ BHN boolit and with sizing it come up with an air cooled drive band BHN? I have sized down right after water quenching and results showed 1-2 BHN softer on the drive bands vs the rest of the boolit, definitely does not work soften the bands down to air cooled WW BHN of 12-13 BHN.

If what you say about work softening on the drive bands to an air cooled BHN then why would anyone worry about too hard of a boolit? The bands would be soft as air cooled and obturate to fit the bore.......

[white eagle]

you may very well be able to see a slight difference in appearance
if you can test the hardness that will tell