Boolit sizing..does it matter much?

[sniper]

O.K., dumb questions...My revolver throats measure .358, and barrel groove diameter is .3567, measured by Dardas before they went out of business. I ordered some boolits from an on-line company which has very good reviews and good service. I ordered them sized .358, and measuring the received boolits randomly, I find the diameter is consistently .3575. I have some beautifully cast boolits of the same weight/style from a forum member that measure consistently .358. Will that little small difference be detrimental at all atall, or should I just order .359", sizing them with a Lee .358 die, and call it good, or...does that small a variation matter much (if at all) to an everyday non-match competitor?
Thanx!

[sigep1764]

Its prolly not much info for ya, but load some and shoot them. Worst thing is you get a little light leading, best thing you get no leading. Light leading is easily cleaned out, but I think you will be ok. I have a Colt with tight chambers that gets a little light leading on the forcing cone. It comes out with a bore brush.

[Bazoo]

It won't matter at all. The difference in alloy and lube will be more of an influence with regards to leading, accuracy, and performance.

[RogerDat]

Shooting will tell.

If shot with same powder and load it will tell you which bullet works better for that load. A different powder or load amount of that same powder might favor the other bullet.

Only if the bullets are identical profile & weight with the only difference being the diameter will you have a direct apples to apple compare of a given powder and load.

I don't think you will find either one "bad" to shoot but you might well find one better. If you feed them back through the cylinder forcing cone do they feel about equally snug, is either one too tight or sloppy? If not then just shoot them and see is best approach.

[JBinMN]

I would shoot them first , then see...

Right now there is no other problem than you received some boolits that were not to spec, but still are oversize to the bbl., even if they are a little undersize for the throat sizes by your measurement. There could be the possibility that they are ok for the throats, and it is best then for you to try to see how they fit thru the throats.

Maybe they will go thru too easy , or maybe you will find they are still just right & constrict just a bit to go thru the cylinder throats & will be ok for that "test" for "that" revolver. Since they are oversize to the groove diameter, by your measurement , then they could possibly work in you revolver just fine, as well.

If the commercial lube is unsatisfactory, then you will also find that out by shooting them, & not likely before hand. And deal with that accordingly afterwards

So I would shoot them first after doing those things before being too concerned about anything.

As far as the boolits you got from a member here, same thing. Shoot them & then see if you need to take more steps ( & more time & expense) to adapt to the 2 types of boolits you are asking about.

Until ya check things & shoot some of them, you really won't know how they do, in regard to fit, lube or even powder type&charge for accuracy from POA to POI.

Go shoot them! & G'Luck! I hope they work out great for ya!


ETA: It appears RD posted just before I did & I did not see it until I was done.

It seems that there is an echo & that is , Go Shoot them & find out!

[georgerkahn]

I do not believe the scant difference in size will have much affect on where the fired bullet hits, all else being the same. A way I look at size -- in a very basic fashion -- is if your bullet is a tad too small, some gasses will go between the bullet and barrel -- not good for any part. A twelve-dollar word, "obturation" is what you're after. Think of whacking the bullet smartly with a hard hammer, and it will indeed squesh out. The fit of the bullet in your barrel should be snug enough to enable the powder to do similar to the hammer blow moving your lead alloy into the rifled barrel grooves maximizing both its snugness -- to propel it where you aim, and making it spin to provide stability. IF the bullet is really too big pressures increase, and I'd suggest if you're loading maximum charges, this could be problematic.
In my experience, the greatest consequences of bullets being a hair "not-perfect" is an increase in leading. And, I've found that in most loads, using gas checks attenuates this.
From your having taken measurements, imho you're "way ahead of the game" and again, other than perhaps a scant change in leading, should have no problems.
Good luck!
geo

[tazman]

The previous comments provide pretty much all the information you need. I will add one item.
Your chamber throats measure .358. Going any larger is a waste of time since the boolits will swage down to .358 when they pass through the throats in any case if they are larger.

[BAGTIC]

No swaging die made will make a bullet that fits your barrel better than will your barrel. A lead bullet would need to be very much oversize to have significant effect and that would be better than a undersized bullet.

[cwtebay]

Along these lines - would truncating the bullet base help? I have pulled apart several original 41 Long Colt, 38wcf, etc and found the base to be hollow. I have inferred that this is to provide an expansive skirt to "seal" the bullet against the bore. Is this correct?
Thank you!

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[Dusty Bannister]

cwtebay, I do not think "Truncating" is the word you are looking for. It is common to describe the conical nose of a bullet as a "truncated cone" You may be thinking you want a hollow based bullet.

Now, back to the OP. You may find that the different bullet lubes used will make a bigger difference in bullet impact than a small difference in diameter. Like other have mentioned, actually firing the bullets will allow the firearm to tell you what it wants. Just remember you are changing the barrel condition when you change lubes, so shoot enough test loads to establish a new and consistent bore condition before you place any money on which bullet does better. Good luck. Dusty

[cwtebay]

cwtebay, I do not think "Truncating" is the word you are looking for. It is common to describe the conical nose of a bullet as a "truncated cone" You may be thinking you want a hollow based bullet.

Now, back to the OP. You may find that the different bullet lubes used will make a bigger difference in bullet impact than a small difference in diameter. Like other have mentioned, actually firing the bullets will allow the firearm to tell you what it wants. Just remember you are changing the barrel condition when you change lubes, so shoot enough test loads to establish a new and consistent bore condition before you place any money on which bullet does better. Good luck. Dusty

Dusty Bannister, you are correct with your application of "truncating". I had a piece made for creating hollow based bullets by a machinist who called his creation a "truncator" (truncater?). But I do agree that the term means to shorten.

However, my question is if this does help with leading given the bore discrepancy described?
Thank you.

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[Dusty Bannister]

It would probably only expand the body of the bullet to fill the gap in a bump die. Other wise you would just have a large base and no real difference at the shoulder. If they are hard cast, probably not a good idea unless using a swage press. Maybe not even then. I would try a few applications of tumble lube before I tried bumping up a hard cast bullet. (no BHN has been mentioned) Dusty

[Ohio Rusty]

If I don't size the boolits, they won't fit in the mouth of the case and I can't load them. I'm speaking about .38/.357 and .44 special and magnum.
Ohio Rusty ><>

[tazman]

If your boolits are too large to fit inside the mouth of the case even when the case is flared, they will have to be sized enough so that is possible. You need to determine the size your gun needs.
In your case, they need to fit the cylinder throats.

[DougGuy]

Whatever you choose to do, loaded ammo must still fit in the chambers so if you size to .359" and you have .358" throats, they may not chamber fully without force.

You can size a cast boolit to .358" and let them sit for some weeks or months, and depending on the antimony in the alloy, they will grow as they age harden, not unusual to see .0003" to .0006" greater diameter after sitting a few months.

For this reason, you need a little wiggle room in the throats, I always size 35 caliber throats to .3585" ~ .3588" and urge the customer to size boolits to .358" which is ideal, the boolit will have a light drag fit in the throats and this is correct.

Also, unless you are using really hard alloy, a full house magnum load will obturate the boolit as it is fired, and it will exit the front of the cylinder at throat diameter, regardless of what it measured when you dropped the hammer.

As far as being oversize affecting accuracy, this is simply not true at all. I have a Uberti Old West (avatar pic) with .4565" throats, I size the 454190 to .456" and it fires through a .451" barrel with great accuracy and zero leading. I have not needed to clean the barrel as long as I have owned this gun. We have one member here that uses a 45 Colt cylinder in a 44 caliber SBH and it shoots great.

The best results will be found with a boolit that is .001" to .002" greater than groove diameter of the barrel, and cylinder throats sized .0005" to .001" over boolit diameter. This works with any center fire revolver, any caliber.

[cwtebay]

Whatever you choose to do, loaded ammo must still fit in the chambers so if you size to .359" and you have .358" throats, they may not chamber fully without force.

You can size a cast boolit to .358" and let them sit for some weeks or months, and depending on the antimony in the alloy, they will grow as they age harden, not unusual to see .0003" to .0006" greater diameter after sitting a few months.

For this reason, you need a little wiggle room in the throats, I always size 35 caliber throats to .3585" ~ .3588" and urge the customer to size boolits to .358" which is ideal, the boolit will have a light drag fit in the throats and this is correct.

Also, unless you are using really hard alloy, a full house magnum load will obturate the boolit as it is fired, and it will exit the front of the cylinder at throat diameter, regardless of what it measured when you dropped the hammer.

As far as being oversize affecting accuracy, this is simply not true at all. I have a Uberti Old West (avatar pic) with .4565" throats, I size the 454190 to .456" and it fires through a .451" barrel with great accuracy and zero leading. I have not needed to clean the barrel as long as I have owned this gun. We have one member here that uses a 45 Colt cylinder in a 44 caliber SBH and it shoots great.

The best results will be found with a boolit that is .001" to .002" greater than groove diameter of the barrel, and cylinder throats sized .0005" to .001" over boolit diameter. This works with any center fire revolver, any caliber.

Man I enjoy this forum!! I never cease to learn. Thank you all.

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[Wayne Smith]

In re your question about 'truncating' - you are comparing apples and oranges. The 41 Colt and the 22 and other older cartridges use heeled bullets because the outside of the bullet is the same diameter as the outside of the cartridge case. The bullet thus has a heel, a reduced portion to fit into the case. The Russians convinced us through experience that having the bullet the same size as the inside of the case was better - look up the history of the 44 American and the 44 Russian.

When using a heeled boolit a hollow base encourages the heel to expand to match the bore.

[Hi-Speed]

.358 is what I use in my Ruger Blackhawk. Years ago (1970s) I started out using .357 cast bullets and they leaded terribly and accuracy was barely passable. Went to .358 and problems went away.