Does sizing actually matter at all?

[Wardo1974]

I was reading through a 1940's vintage reloading manual written by Philip Sharpe, the Complete Guide to Handloading.

In it, he talks about sizing bullets, and he cited an experiment whereby bullets were loaded and fired as much as .006-.008 overbore. His conclusion was that they shot fine with zero accuracy or pressure problems, and that as long as bullets are sized at least .001-002 larger than the bore, then they are fine to use.

Given this, why bother with slugging your bore looking for that exact .001-.002 overbore measurement? I recently loaded some .45-70 rounds into my 1886 Browning, which I'd previously slugged to be about .458. The boolits I loaded came out at .463-.464. I loaded and fired them, and noticed absolutely nothing but tight groups (better than the .460's I'd been using!)

So I'm asking, why not simply use a boolit several thou larger than bore diameter and forget about slugging for the "perfect" bullet size? If it's too large, the act of firing it swages it down to the right size anyway, doesn't it?

[17nut]

I was reading through a 1940's vintage reloading manual written by Philip Sharpe, the Complete Guide to Handloading.

In it, he talks about sizing bullets, and he cited an experiment whereby bullets were loaded and fired as much as .006-.008 overbore. His conclusion was that they shot fine with zero accuracy or pressure problems, and that as long as bullets are sized at least .001-002 larger than the bore, then they are fine to use.

Given this, why bother with slugging your bore looking for that exact .001-.002 overbore measurement? I recently loaded some .45-70 rounds into my 1886 Browning, which I'd previously slugged to be about .458. The boolits I loaded came out at .463-.464. I loaded and fired them, and noticed absolutely nothing but tight groups (better than the .460's I'd been using!)

So I'm asking, why not simply use a boolit several thou larger than bore diameter and forget about slugging for the "perfect" bullet size? If it's too large, the act of firing it swages it down to the right size anyway, doesn't it?

If you dont slug then what is bore + a couple of thousands?

As long as the bullet is to large gas cutting/leading is avoided and that is the main thing.

[dragon813gt]

I don't slug my barrels. I have enough sizing dies to try different sizes. I don't shot military surplus rifles so the bores are consistent. I'm not a fan of pounding anything through a barrel. I know it works for many but I've found it unnecessary.

[Dusty Bannister]

For me, the slugging of the barrel is easier than doing a chamber cast. One gives you the minimum necessary for not leading, the other gives you the maximum safe diameter of bullet/case mouth thickness that can be used. But then you need to also measure the case mouth thickness of various makers to stay below the max figure and also allow for clearance. Keeping it simple seems a good idea.

[Maven]

"So I'm asking, why not simply use a boolit several thou larger than bore diameter and forget about slugging for the "perfect" bullet size? If it's too large, the act of firing it swages it down to the right size anyway, doesn't it?" ...Wardo1974

The answer is "It depends...." I've tried sizing to various diameters in both rifles and revolvers and found that size really does matter, although it would be quicker to avoid that chore. However, I do try several different plain based CB's in my .30-06 with light powder charges and am pleased with their accuracy. One of them, a Lee 30-150-TL (group buy here years ago), drops from the mould @ .317" (base), but that doesn't seem to handicap it. Gas checked CB's, OTOH seem to do better when sized to fit the rifle.

[DougGuy]

That was the 1940s, Ruger hadn't yet invented the Blackhawk revolver, Colt's were still in the first generation, 1911s would gladly chamber a .453" boolit.

I think it's safe to say that rifle chambers and revolver cylinder throats were quite generous in that period of manufacture. Look at the Colt SAA cylinders vs. groove diameter, and the S&W model 1917, both being sized so a .452" boolit would fall rattling through the throats. I wonder what size factory ammo was for just the .45 Colt cartridge in those days? The .45 Schofield called for a .454" boolit.

In the time that article was written and even many years later, sizing was an unnessary step. Nowdays, you can't even get .45 ACP loaded with a .452" boolit to go fully into a chamber, or a .45 Colt loaded with a .452" boolit to fully chamber in a modern cylinder unless throat resizing has been performed.

So much for the term "match grade."

[mdi]

Sizing bullets to barrels is kinda like buying britches. You can go to the store and try on a bunch of different sizes and perhaps eventually you'll find a pair that fits, or you could measure your waist and know what size to buy...

[runfiverun]

you might know what size to buy but the Chinese measure in metric.

when you shoot an oversized boolit your squeezing it down.
this makes it longer.
the rifling is displacing more metal.
that extra metal can only go 2 directions and the boolit is going one of them.
which leaves the back or steering end of the boolit to be damaged or for those little ribbons of lead to be pushed to.
I like square bases on my boolits I make them that way, I like to keep them that way until they leave the muzzle.
distorting them right at the start of the hole is not on my list of how to do things.

[beagle]

For many years, with Lyman's (and other manufacturer's) tendency to produce moulds which cast undersize bullets, slugging the bore was a necessity to insure that we cast a bullet that was big enough to fit the bore. In those days, not so much to insure bore fit but to insure that bullets were big enough. Now, with custom makers producing moulds which cast bullets closer to desired diameter and larger, slugging is sometimes necessary to produce a ready to load cast projectile that is large enough to fit the bore and at the same time small enough to load in a cartridge and still chamber freely. No matter how large the bullet is, if it will chamber and fire, the pressure will swage it down to fit the barrel. The old thinking of Sharpe's day was to have a bullet that perfectly fit the barrel and even today, we can't say that's wrong as the groups shot by Harry Pope and many of the old timers using breech seating still stand today as outstanding, if not in some case, records. The unknown is what makes casters strive for perfection and attracts shooters to the game./beagle

[mdi]

Hmmm. A while back on a forum, I quoted Sharpe on the .006"-.008" oversize bullets and was quickly "corrected" (flamed) as that would cause a "dangerous rise in pressure"...

[Wayne Smith]

... Which is why many say that the throat measure is the important one, not the bore. It has been said here many times, if you can chamber it, shoot it. Lead squeezes nicely.

[nicholst55]

Elmer Keith used to regularly shoot nominal .458" diameter boolits through .45 Colt SAAs. He blew more than one of them up, too.

[dubber123]

Elmer Keith used to regularly shoot nominal .458" diameter boolits through .45 Colt SAAs. He blew more than one of them up, too.

I'm guessing ole Elmer had them stuffed about as full of powder as possible too though ;)

[ohiomadman]

Hmmm. A while back on a forum, I quoted Sharpe on the .006"-.008" oversize bullets and was quickly "corrected" (flamed) as that would cause a "dangerous rise in pressure"...

.006-.008 is nothing. I once accidently shot a couple of .358 boolits down a .308 barrel. No Kabooms, just sounded kinda funny.

[Victor N TN]

I've grown rather fond of my ugly face, hands and fingers. I think I'll stick with .001" over size and let that be the end of it for me. I have enough scars and wrinkles. I don't need to be purposely making any new ones.

[Boogieman]

Elmer wrote about sizing 300 gr. 49/90 bullets down to use in a 45 Colt over 35gr. of 3f black powder.

[lotech]

I've accumulated many sizing dies over the years, so slugging a bore is not necessary. A cast bullet a few thousandths over hurts nothing and is often beneficial for accuracy, but there are limits. In rifles, I shoot more .308 and .30-06 than anything else and have found, generally, that either a .310" or .311" works best in most guns. I'll usually find that accuracy diminishes, at least slightly, with a bullet sized to .312". Going the other direction, a .309" bullet may also contribute to a decline in accuracy.

Some moulds cast just right and sizing is not needed. It's easier though to apply lube with a lubrisizer using a die large enough so that no sizing occurs; only lube is applied.

[Wardo1974]

At this time, I would like to point out that I was using pure lead boolits when I tried this out. Obviously they would swage down to the size of the barrel a lot easier than an alloy might, and it is thus incorrect to assume that this works for everything as a rule of thumb.

[bedbugbilly]

Isn't another factor is if you want to shoot a larger boolit - say .006 - .008 oversize of the bore - whether or not if you can get it stuffed into the case mouth and whether it will chamber?

I have a 45 Colt (uberti cattleman) that has extremely generous size chambers. The throats are about .454 though and I can easily chamber a 454-190 255 gr. RNFP boolit that falls from the mold at .4545 to .455 - and the bore slugs out at .452. I don't load near max and it works just fine and is accurate.

But . . . I have a GEW98 8mm Mauser - 1905 Danzig - that the bore measures out to .323. I have a NOE 130 ish grain FN mold that was a group buy a while back. It's a .325 and if I load them in brass and try to chamber them, they are too tight. Size them to .323 and they work just fine. I have an extra Lee .323 push through sizer that I'm going to gently open up to .324 to see if that will work . . . but again . . . is it not dependent on if they will chamber as well?

[Wardo1974]

Isn't another factor is if you want to shoot a larger boolit - say .006 - .008 oversize of the bore - whether or not if you can get it stuffed into the case mouth and whether it will chamber?

I have a 45 Colt (uberti cattleman) that has extremely generous size chambers. The throats are about .454 though and I can easily chamber a 454-190 255 gr. RNFP boolit that falls from the mold at .4545 to .455 - and the bore slugs out at .452. I don't load near max and it works just fine and is accurate.

But . . . I have a GEW98 8mm Mauser - 1905 Danzig - that the bore measures out to .323. I have a NOE 130 ish grain FN mold that was a group buy a while back. It's a .325 and if I load them in brass and try to chamber them, they are too tight. Size them to .323 and they work just fine. I have an extra Lee .323 push through sizer that I'm going to gently open up to .324 to see if that will work . . . but again . . . is it not dependent on if they will chamber as well?

When I asked my question, I overlooked this part, basically because...I can't shoot it if it doesn't chamber. I'd have to think that yeah, if you have to jam them in there, it isn't going to work, or if it does, in that instance just might produce pressure issues.

Those big boolits in my 1886 dropped in neat as you please, so I had no worries at all. My main thought on it was, I wanted to know what the greybeards on the forum here thought about shooting a boolit that big.

[JonB_in_Glencoe]

If you're not gonna size the boolits and your batch of boolits range in size plus or minus a few thou...you'll get inconsistent pressures, even though you may not be getting into a dangerous situation, it'll give you inconsistent accuracy.

[Wardo1974]

For those interested, this is the manual I read it in. It's page 107 of this pdf, which in the paper copy of the book is page 98.

A few things I see as I read it again - he said being a few thousandths overbore had no impact at all on accuracy with soft alloys such as 1 in 30, and also with more and deep driving bands, "which would readily swage down .003 or .004 without causing serious trouble in the form of bullet mutiliation or severe pressure."

This book is a great read. http://photos.imageevent.com/badgerdog/generalstorage/pdfpublications/complete_guide_to_handloading%20-%20sharpe%20-%201937.pdf

[rintinglen]

A ways back, there was an article in the Rifleman that showed that there was a negligible rise in pressures with boolits up to .003 oversize. Beyond that, you got increases that could be troublesome, ie. 3500 psi (IIRC) when you got up to the largest ones they tried, easily enough to run a regular load into +p territory. I have had tooo many instances of over-sized boolits preventing rounds from chambering. Consequently, I size all my boolits, plus I like being able to hit close to where I aim.

[bangerjim]

That was then..........this is now.

I ignore all that stuff in those old manuals that was "FACT" back in the dark ages. Nice intertaining reading but I use moder up-to-date data and methods. 0.002 over is my rule. With PC on everything.


And it give a nice uniformity to the boolits, rather than relying on whatever the mold happens to drop. Sizing gives PC a polished cool shiny uniform look. I like it.

I have never loaded-as-dropped boolits an any of the many cal's I reload for.

Why skip that quick and very necessary step in your hobby!?!?!?!?!?!

[melloairman]

you might know what size to buy but the Chinese measure in metric.

when you shoot an oversized boolit your squeezing it down.
this makes it longer.
the rifling is displacing more metal.
that extra metal can only go 2 directions and the boolit is going one of them.
which leaves the back or steering end of the boolit to be damaged or for those little ribbons of lead to be pushed to.
I like square bases on my boolits I make them that way, I like to keep them that way until they leave the muzzle.
distorting them right at the start of the hole is not on my list of how to do things.
I agree and leading the barrel for the first few inches out of the lead is greatly increased . And not on my list of things I want to clean up after .Marvin

[dverna]

you might know what size to buy but the Chinese measure in metric.

when you shoot an oversized boolit your squeezing it down.
this makes it longer.
the rifling is displacing more metal.
that extra metal can only go 2 directions and the boolit is going one of them.
which leaves the back or steering end of the boolit to be damaged or for those little ribbons of lead to be pushed to.
I like square bases on my boolits I make them that way, I like to keep them that way until they leave the muzzle.
distorting them right at the start of the hole is not on my list of how to do things.

Where does the extra material go if a .312 bullet is sized to .310?

[runfiverun]

if your lube groove angles are designed properly they actually give that extra lead somewhere to go.
if your using a pre-slumped boolit design and a low tin/antimony alloy the extra lead can go to the rear of the drive band also but it can flow to the area in front of the front drive band at the start as the nose slides back on itself under sever acceleration.
and more towards the rear of the back drive band as the boolit enters the rifling further.

if a boolit relying on a mechanical fitment is used a harder alloy can help since it will hold the rifling on it's own accord but it still has to have open spaces for the lead the rifling is moving to go.

the key is to not let the extra alloy flow to the base of the boolit where you can have a trailing edge failure or extra lead pushed back over the gas check.
the angles and depth that a lube groove is cut can help or hurt soak up that extra displaced metal.
but it can only take so much so the whole boolit tries to get longer to fit the hole it's being shoved into if you have a to big boolit.
now if the leade angle from the throat into the rifling is fairly sharp it can push even more lead back or even scrape it off and leave a ring of lead behind in the front of the chamber.
if the alloy is soft or a complete mis-match to the pressure rise speed of the powder your using it will open up into that available area in front of the case mouth [riveting] and quite often you'll see it stuck to the front of the case,
or possibly a streak of lead right at the start of the rifling.

[MT Chambers]

Most of my rifles would not chamber a cartridge loaded with a bullet that was .006-.008 oversize.

[Bird]

Wardo,
Measure the inside neck diameter of a fired case, and that will be about the largest diameter bullet that should fit your chamber. That would only allow you a thou or so for brass spring back, so you will be running with very little cartridge clearance in the chamber. If you are running different brands of brass you may want to make a few measurements.
My Miroku 1886 fired brass has an inside neck dia of 0.460'', maybe 0.461'', so I suspect I would have trouble with bullets of you diameters.

[imashooter2]

I shoot the vast majority of my castings unsized and film lubed. The gas checked and conventionally lubed boolits are done in dies that barely touch the sides. I'm a firm believer in distorting the boolit the least amount possible.

[old turtle]

Wow! this gets complicated for me. I size most bullets. But I have some rifles which shoot better un-sized. I try to size about 1 thou. over but again it depends on the rifle. I have found it is another variable relating to cast bullets along with hardness, shape and powder used. My older single shot rifles like the unsized bullets. I once had a older single shot rifle which would only shoot one bullet with a specific powder. Anything else was all over the place. I do sometimes slug barrels but you should use straight soft lead to do it.

[mdi]

An aside; A while back I read an article about a feller that made a .22/.17 barrel for his rimfire rifle. He was shooting .22 lr ammo and the bullets came out the end of the barrel .17 caliber. No real problems...

[BAGTIC]

Often results are counter intuitive. For example NRA study showed that jacket bullets with hard lead core produced less pressure than same bullets with soft lead core.

As for oversized lead bullets producing dangerous pressures it might be possible is one worked up a maximum pressure load with minimum diameter bullets and then substituted very large bullets with the same adjusted charge. Considering that it would be considered bad loading practice to work up a max load with jacketed bullets, which are generally held to much tighter tolerances than cast bullets, and to then switch to another bullet without working up that load first it seems there should be no significant difference. Difference due to alloy density (weight) and hardness of themselves would seem to mandate working up a new load. Anyone who starts off 5-10% low should not even approach any dangerous pressures. My rule is if they chamber shoot them. I have never had any problem with any lead load that will chamber, probably because I worked up all my loads from start and not by blindly substituting another bullet.

[beagle]

Another factor along this line is your seating die. Many will not seat oversize bullets. The tolerance is too close. I ran into this in two situations. I had some .433" bullets for the .44 SBH and the crimping shoulder kept seating them causing all kinds of hair pulling and I don't have much to spare. The second was with a .45/70 mould I had opened and made a .462" sizer. Same problem. Both instances were cured by relieving the seating die several thou in a Sunnen grinder. The .433" bullets loaded were fairly hard to chamber so I decided that .433" was too much of a good thing and dropped back to a sizer that runs .431+. If you mess too much with oversize bullets, you sooner or later run into die problems./beagle

When I asked my question, I overlooked this part, basically because...I can't shoot it if it doesn't chamber. I'd have to think that yeah, if you have to jam them in there, it isn't going to work, or if it does, in that instance just might produce pressure issues.

Those big boolits in my 1886 dropped in neat as you please, so I had no worries at all. My main thought on it was, I wanted to know what the greybeards on the forum here thought about shooting a boolit that big.

[10x]

I size to the largest diameter that will easily chamber in the rifle -
I have one Remington 700 in 308 win that requires a 0.309" bullet to allow easy chambering A couple of other 308s will allow a 0.311" bullet to chamber easily.

[John Boy]

...and that as long as bullets are sized at least .001-002 larger than the bore, then they are fine to use. That's the rule of thumb with GG Pb bullets. I've shot with accuracy as cast one that are 0.003 over bore. The issue going much larger is decrease in velocity and increase in pressure

[blikseme300]

if your lube groove angles are designed properly they actually give that extra lead somewhere to go.
if your using a pre-slumped boolit design and a low tin/antimony alloy the extra lead can go to the rear of the drive band also but it can flow to the area in front of the front drive band at the start as the nose slides back on itself under sever acceleration.
and more towards the rear of the back drive band as the boolit enters the rifling further.

if a boolit relying on a mechanical fitment is used a harder alloy can help since it will hold the rifling on it's own accord but it still has to have open spaces for the lead the rifling is moving to go.

the key is to not let the extra alloy flow to the base of the boolit where you can have a trailing edge failure or extra lead pushed back over the gas check.
the angles and depth that a lube groove is cut can help or hurt soak up that extra displaced metal.
but it can only take so much so the whole boolit tries to get longer to fit the hole it's being shoved into if you have a to big boolit.
now if the leade angle from the throat into the rifling is fairly sharp it can push even more lead back or even scrape it off and leave a ring of lead behind in the front of the chamber.
if the alloy is soft or a complete mis-match to the pressure rise speed of the powder your using it will open up into that available area in front of the case mouth [riveting] and quite often you'll see it stuck to the front of the case,
or possibly a streak of lead right at the start of the rifling.

Very interesting as I have pondered on what you have put nicely into words I can understand. I don't understand how the designs without grooves that are for PC won't distort the base and nose when swaged through the rifling and can still be consistent in accuracy. The alloy must be displaced to accommodate the changed dimensions of the rifled barrel and so without the spaces left by the lube grooves the base and nose are the only place to go, not good in my book.

[JohnH]

That was the 1940s, Ruger hadn't yet invented the Blackhawk revolver, Colt's were still in the first generation, 1911s would gladly chamber a .453" boolit.

I think it's safe to say that rifle chambers and revolver cylinder throats were quite generous in that period of manufacture. Look at the Colt SAA cylinders vs. groove diameter, and the S&W model 1917, both being sized so a .452" boolit would fall rattling through the throats. I wonder what size factory ammo was for just the .45 Colt cartridge in those days? The .45 Schofield called for a .454" boolit.

In the time that article was written and even many years later, sizing was an unnessary step. Nowdays, you can't even get .45 ACP loaded with a .452" boolit to go fully into a chamber, or a .45 Colt loaded with a .452" boolit to fully chamber in a modern cylinder unless throat resizing has been performed.

So much for the term "match grade."

I beg to differ some here. I have a Smith and Wesson Second Model in 44 Special. The chamber throats and barrel groove diameter are a very good .430 on the chamber throats and the barrel slugs at .429 Couldn't ask for better. I once had a S&W 29-3 which was lousy on chamber throat and barrel dimensions and out of time as well.

I've had several Blackhawks in 45 Colt and my current one is a joy to shoot. At the same time I have a Dan Wesson which measures at .430 on the chamber throats but the barrel is a .426 groove diameter. It is one of the most accurate revolvers I've ever shot but will lead at the juncture of the barrel throat/lands and grooves like crazy. Takes about 300 rounds for the leading to reach the point of negatively affecting accuracy

[JWFilips]

My Take: is A bit Fatter is Better then A bit Skinny; I find this holds true for Cast Boolets and Ladies! On average you will have a better time with them! To Be sure you can go on trying to PC a skinny boolit but as for the ladies I don't like "Plastic"[smilie=1:

[Shiloh]

If you don't slug, what is your reference measurement??

Shiloh

[10x]

If you don't slug, what is your reference measurement??

Shiloh

The largest diameter cast bullet that will chamber easily without the neck touching the wall of the chamber.
This means the throat of the bore just in front of the chamber will size the bullet.
This method works extremely well in the 303 British where bore diameter can be 0.315" or larger.

It is helpful to know the diameter of the neck area in the chamber so that reloaded cartridges can be 0.002" smaller than the diameter of the neck in the chamber.

[Chihuahua Floyd]

For my 44 Mag Marlin it matters. If I load up "as cast" bullets, eventually one will chamber hard. case sticks in chamber and I have to use a rod to poke it out.
When I size my bullets to .429 I get good accuracy and nothing sticks.
ymmv
CF