9 BHN casts

[castmiester]

I bought a RCBS 44-240-SWC 240 mold for my 44 mag, as you know has no gas check. I guess I have to harden the alloy unless I load 44 Special velocities. I have heard in the past as long as you don't load to high velocities it won't gas cut.

[Thumbcocker]

I push plain base acww boolits to 1400 in .44 mag with zero leading. Fit is king.

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[castmiester]

I push plain base acww boolits to 1400 in .44 mag with zero leading. Fit is king.

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yeah but at what alloy ?

[Thumbcocker]

Acww= air cooled wheel weights.

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[Dusty Bannister]

The OP could cast, lube and size and let them age harden and then work up a load until accuracy falls off or leading begins and then back off the load a bit. He might find a very accurate load before he reaches whatever tolerance level he has since he has no stated velocity goal.

Heat treat and quench is also an option, and use whatever alloy he already has.

[castmiester]

The OP could cast, lube and size and let them age harden and then work up a load until accuracy falls off or leading begins and then back off the load a bit. He might find a very accurate load before he reaches whatever tolerance level he has since he has no stated velocity goal.

Heat treat and quench is also an option, and use whatever alloy he already has.

Book velocities.. like 1400. Don't want to invade the kitchen oven. Have you tested aged casts ?

[Thumbcocker]

Acww in rifles with gas checks at over 2000 fps. Most of my boolits, handgun and rifle,, sit around for up to months before being shot.

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[castmiester]

I have data for my one book one caliber loads RCBS casts, but it doesn't specify what alloy.

Does any one have the One book one caliber 44 mag RCBS cast data ?

[Hick]

I generally make all my pistol caliber bullets of a blend that runs about 9 BHN, some plain based with tumble lube, others plain based with PC. As mentioned above, fit is most important. The fastest I have gone with 9 BHN and tumble lube is 1050 fps. Faster might work, but I just haven't tried it.

[Rattlesnake Charlie]

I shoot an out of production Lee 265 gr SWC in .44 mag at velocities over 1200 fps. Allow is half range scrap and half COWW. Lube is Bull Shop soft. Don't know what that BHN is. No leading.

[gunseller]

I have loaded to 1550fps with the same bullet mold you have. 50/50 mix of coww and pure lead. Lube is my own. Soft and slimy. No leading and great accuracy. Shot deer at around 200 yards with a Ruger SBH. It also shoots well in my Rossi.

[dtknowles]

Oh, so many variables.

First fit is king and goes double with revolvers because you have to fit to two things, the throats and the barrel. The throats must be bigger than the barrel and you must load bullets sized to the throat.

If you are not going to use an alloy harder than 9 bhn then yeah, you can't push them to maximum pressures/velocities.

With hardball or Lyman #2 or equal hardness you don't need a gas check even at 44 Mag. max. loads, other supermags are a different story, maybe. With good fit and a good bore. Bad fit, bore choke or rough bore leading is likely.

Tim

[JonB_in_Glencoe]

You ask too many questions.
Just load 'em up and shoot 'em.
If you have a problem, then ask a question.

[castmiester]

I shoot an out of production Lee 265 gr SWC in .44 mag at velocities over 1200 fps. Allow is half range scrap and half COWW. Lube is Bull Shop soft. Don't know what that BHN is. No leading.

Good to know thanks. I probably didn’t need GC on my .357. Other than that, no leading. Used NRA lube, worked good. But was curious if the 44 would be a problem with softer alloy.

I made ingots about 3-4 years ago and some casts, shot them awhile back and didn’t see any leading. Not really on board with aging alloy getting harder. Within the last month or so they are the same BHN, 9. Thanks for sharing your experience it saves me from making unwanted ones. ��

[405grain]

I've shot 245 grain RCBS plain based SWC's at 1200fps (4" barrel S&W 629) with no problems. The alloy is acww, but I powder coat instead of lube. Using PC you can sometimes get away with softer alloy, or can use a semi-hard alloy without a gas check.

[castmiester]

Oh, so many variables.

First fit is king and goes double with revolvers because you have to fit to two things, the throats and the barrel. The throats must be bigger than the barrel and you must load bullets sized to the throat.

If you are not going to use an alloy harder than 9 bhn then yeah, you can't push them to maximum pressures/velocities.

With hardball or Lyman #2 or equal hardness you don't need a gas check even at 44 Mag. max. loads, other supermags are a different story, maybe. With good fit and a good bore. Bad fit, bore choke or rough bore leading is likely.

Tim

I'm aware of groove fit and throat fit. My throats are .4325 consistently, and the groove is .431. I have a mold coming monday and the seller said it casts .433 and have to get a .432 custom lube sizer from Buffalo arms or someone else, or buy a .431 and have it honed out to .432 and make a plunger with it.

[RickinTN]

Fit is King. It's not velocity which is the cause for leading and gas cutting, it's pressure. Good reading from the Las Angeles Silhouette club can be very educational. The link should be found at the bottom of this page.
Good Luck,
Rick

[Forrest r]

Velocity has nothing to do with. It's all about the load/pressure.

The majority of my casting/shooting (90%+ since the 1980's) needs is done with 8/9bhn range scrap. Playing around shooting 8/9bhn 250gr rf hp's in a 44mag 10" bbl'd contender. Using a pretty stout load of unique (11.5gr).
https://i.imgur.com/AK9xTG0.jpg

10-shot group playing around with a 308w @ 50yds using 8/9bhn cast bullets and no gas check (13xxfps).
https://i.imgur.com/xORGXOf.jpg?1

Another 10-shot group @ 50yds with 8/9bhn cast bullet and no gas check (1700fps).
https://i.imgur.com/BJ3ovpc.jpg

Velocity shouldn't be in conversation.

[RickinTN]

I'll also add: You would do better to size your bullets through a Lee or other push through die and apply the lube through a lubesizer die which is .001" or so larger than your finished bullet diameter. This way you get a straight and concentric bullet and the lubesizer die doesn't get the chance to pull it's nasty tricks on your bullets.
Good Luck,
Rick

[castmiester]

I'll also add: You would do better to size your bullets through a Lee or other push through die and apply the lube through a lubesizer die which is .001" or so larger than your finished bullet diameter. This way you get a straight and concentric bullet and the lubesizer die doesn't get the chance to pull it's nasty tricks on your bullets.
Good Luck,
Rick

I have Lyman lube sizer dies yes. They are not .001 larger. And I do believe you guys are splitting hairs in regards to velocity, increased velocity increases pressure.

[JonB_in_Glencoe]

No one is splitting hairs.
Faster burning powders spike (pressure) sooner as velocity increases, whereas slower burning powders spike later.
This is why there is a general practice of using faster burning powders for lower velocity loads, and slower burning powders for higher velocity loads.
Gas cutting happens when there isn't enough pressure to obturate the boolit. So if you have a undersized boolit, it's more likely to have gas cutting on a low pressure load, than with a High pressure load.

[Thumbcocker]

Respondents are offering sound advice based on a lot of real world experience. Hardly splitting hairs.

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[Bigslug]

Methinks you're sweating hardness a little too much.

You're going to get gas blow-by if you're bullet is too hard to obturate and seal the bore at the pressures involved, or if the "funnel" of cylinder to bore is not an even and true taper, as you might find with bore constriction caused by frame crush. You're running at low speeds (compared to rifles) at a relatively slow rate of twist, and so will not be putting sufficient torque stresses on the bullet to open up a path for gas cutting.

Work up to the level desired. If it leads, look at where the leading is and isn't in the barrel, and assess the problem. If the accuracy begins to fall apart as speeds increase, assess the problem.

[hades]

My target BHN is 9-10 for all my handgun casting, 41 and 44 mag full power loads to 9mm, 40, 45 acp loads.

They all shoot great and no leading.

[castmiester]

No one is splitting hairs.
Faster burning powders spike (pressure) sooner as velocity increases, whereas slower burning powders spike later.
This is why there is a general practice of using faster burning powders for lower velocity loads, and slower burning powders for higher velocity loads.

At the top end of my powders I have, Blue dot will create higher pressures, maybe not lower velocity, yes, BUT say H110 will create lower pressures but still can get the same velocities. So Temps, are the concern no matter what powder you use sure even at lower velocities.
Gas cutting happens when there isn't enough pressure to obturate the boolit. So if you have a undersized boolit, it's more likely to have gas cutting on a low pressure load, than with a High pressure load.

With a good bullet fit, that prevents cutting ?

Any data I see or saw mentions on Lymans three casts that they say are a gas check base bullet. So I assumed that they are needed. Then over the years guys said as long as you stay under 1500 fps you don't need one, but hey never mentioned about alloy into the equation which I never felt fit protected the base from gas cutting, regardless of pressures and that was always brought into the conversation.

[gwpercle]

Fit of the boolit is Much more important than Hardness .

A BHN of 8-9 is perfect for a hunting boolit .

Slug your bore and size your boolits .001" - .002" over and ... load em up .

Most folks shoot boolits that are way too hard in handguns ...
BHN 9 ...You are Good !

Size beats hardness Seven Ways to Sunday in handgun boolits !
Gary

[castmiester]

Fit of the boolit is Much more important than Hardness .

A BHN of 8-9 is perfect for a hunting boolit .

Slug your bore and size your boolits .001" - .002" over and ... load em up .

Most folks shoot boolits that are way too hard in handguns ...
BHN 9 ...You are Good !

Size beats hardness Seven Ways to Sunday in handgun boolits !
Gary

Alot of varying information on the web and jacketed bullets were only designed for high velocity cartridges. So yeah I get it... softer casts can take it in handguns.

[Bigslug]

It all comes down to marketing.

Commercial cast is, or at least was, a lot harder than it needed to be mainly for shipping reasons. If customers opened the boxes to find a bunch of bullets that were dented and with rounded bases from rattling around in a box during shipping, they would not become repeat customers. They're also usually shipped with heat-applied hard wax lubes for the same reason. None of that is optimal, and hopefully they ship on the fat side for functional diameter. Thus began the vendor's pitch of "harder = better", and a lot of folks are swallowing that to this day. Remember, you're being told that by people who are trying to sell you something.

Good fit is going to be king, regardless of how hard you push them. Provided you have that, added hardness mostly becomes an issue for maintaining accuracy as the load intensity increases. I wouldn't sweat it until you reach a point where accuracy drops off, then harden up a little until it comes back.

[JonB_in_Glencoe]

With a good bullet fit, that prevents cutting ?

Any data I see or saw mentions on Lymans three casts that they say are a gas check base bullet. So I assumed that they are needed. Then over the years guys said as long as you stay under 1500 fps you don't need one, but hey never mentioned about alloy into the equation which I never felt fit protected the base from gas cutting, regardless of pressures and that was always brought into the conversation.

boolit fit prevents cutting.

See post #2 in regards to what a GC does...at least that's been my experience. As you read through this thread, you'll see varying theories...I've been in conversations with some of those posters and many of them are the most knowledgeable people I know.

https://castboolits.gunloads.com/showthread.php?41033-The-real-story-on-Gas-Checks

[castmiester]

It all comes down to marketing.

Commercial cast is, or at least was, a lot harder than it needed to be mainly for shipping reasons. If customers opened the boxes to find a bunch of bullets that were dented and with rounded bases from rattling around in a box during shipping, they would not become repeat customers. They're also usually shipped with heat-applied hard wax lubes for the same reason. None of that is optimal, and hopefully they ship on the fat side for functional diameter. Thus began the vendor's pitch of "harder = better", and a lot of folks are swallowing that to this day. Remember, you're being told that by people who are trying to sell you something.

Good fit is going to be king, regardless of how hard you push them. Provided you have that, added hardness mostly becomes an issue for maintaining accuracy as the load intensity increases. I wouldn't sweat it until you reach a point where accuracy drops off, then harden up a little until it comes back.

So someone says this...

Generally speaking, a .431" will be larger than most if not all production made .44 spl/mag revolver barrels. Groove diameter is normally .429" ~ .430" so there really isn't a need to slug the bore. Same with .45 caliber revolvers, unless you are dealing with an old Colt or wartime S&W, it will have a groove diameter nominally .451" so using a .452" boolit is acceptable as being larger than groove diameter.

And then says this....so now maybe you can understand why I ask the questions I do and think what I do.

The easiest thing to do is slug the bore, and without even measuring the slug, see if it will go into the cylinder throats from the front. If all is correct with the throat diameters, the rifled slug you pushed through the bore should slide right into the cylinder throats. If it won't then that tells you right there the throats are smaller than the bore and probably could stand to be reamed and honed to have the gun shooting it's best. Fitment is KING, and for proper fitment, the throats should be sized slightly larger than the groove diameter of the bore, you should be able to slide the slug through them with finger pressure at the most.

or this.... from a guy here who is supposed to be well respected

Gas checks work better when there is a heavy for caliber, softer alloy boolit on top of them

I can't post another comment from the same member, I deleted a PM, but he did say this..

I don't concern my self with barrel dimensions

Ruger groove dimensions have always been .429-.430

[castmiester]

boolit fit prevents cutting.

See post #2 in regards to what a GC does...at least that's been my experience. As you read through this thread, you'll see varying theories...I've been in conversations with some of those posters and many of them are the most knowledgeable people I know.

https://castboolits.gunloads.com/showthread.php?41033-The-real-story-on-Gas-Checks

the guy hasn't posted since 2015.....

this kinda goes along the lines of what you're saying..

The gas check increases the shear strength of the alloy so can allow higher pressure than the alloy alone.
And he doesn't sound he's speaking from experience here...

In fact I think a gas check at pressure below or just barely adaquit of what is needed for obturation may prevent a good seal. Depending on how high the pressure is the base is what will obturate to make a seal.
And here he's along the lines with you..

The higher the pressure the more length of the bullet will obturate.
and here...

If pressure is not high enough to obturate past the check you may loose the seal.

I would say a copper GC prevent damage to the bore. However it should be soft enough to allow obturation of the cast.

[JonB_in_Glencoe]

I'll stick with what I said in post #13.

My comments in post #21 and #29 are how I've experienced this topic. I included the link, so you could see there is varied theories by members. It appears the lowly GC does more than one thing, quite possibly a half dozen things, or more, depending on the various applications/conditions.

[brasshog]

I'm running 44 mag cast boolits at 1200fps (measured) with zero leading issues. They are about 10-11BHN and sized .430. The mix is 93-3-3 alloy.

[castmiester]

I'll stick with what I said in post #13.

My comments in post #21 and #29 are how I've experienced this topic. I included the link, so you could see there is varied theories by members. It appears the lowly GC does more than one thing, quite possibly a half dozen things, or more, depending on the various applications/conditions.

And I'll stick with what I said in post #20. And based on your comment...

If you have a problem, then ask a question.

I ask questions before hand to know what to do, when the problem arises....it's called doing your homework, first.

[SoonerEd]

I have 1,700 lbs of range lead at 8bhn. It seems to do good till about 1,100 w/o gas check. PC seems to get me to 1,200.

[Forrest r]

And I do believe you guys are splitting hairs in regards to velocity, increased velocity increases pressure.

From your 1st post:
"I have heard in the past as long as you don't load to high velocities it won't gas cut."

Interesting:
That 11.5gr load of unique I posted is about max for the 44mag. Lyman lists their 429667/240gr fn at 11.7gr max. My cast bullet actually runs closer to 260gr with that 8/9bhn alloy.

Even though it was shot in a contender (+/-1400fps) I don't want to increase the pressure to 44mag p+ levels. Now I didn't have a problem switching to 2400 and getting +/- 1500fps with the same bullet.

I never bothered to chronograph those loads, nothing more than blammo ammo/plinking loads.

The only reason I chronographed those 308w loads was because I was getting into powder coating bullets (2014) and was doing head to head testing.

This was what I posted, a pc'd bullet using no gc.
https://i.imgur.com/xORGXOf.jpg?1

This is the other 1/2 of the test. Same bullet/same cast alloy (8/9bhn). But this bullet was traditionally lubed (ben's red + a coat of 45/45/10) and had a gc installed. Same 9.0gr load, same rifle, same 50yd 10-shot test on the same day.
https://i.imgur.com/YM89zE2.jpg

You're the one asking about "gas cutting" and velocity.

This is an excellent example of what "gas cutting" is and it's relationship to velocity.

[castmiester]

Good stuff thanks

[Bigslug]

You're not getting any bad advice from what I'm seeing.

One of the key functions - perhaps the key function - of a gas check is to act as a driving key at higher speeds than would otherwise be ideal for hardness of the alloy. This is not so much related to the pressure behind the bullet as it is the rotational torque from the rifling. That torque can get sufficient that the impressions made by the lands want to start opening up. The gas check - being harder - limits this.

Note that this is going beyond mere obturation. At these increased rotational speeds, we've gone beyond the bullet needing to be /soft/plastic enough to seal from being squeezed between pressure from behind and bore constriction from the front. Now we're in a territory where that rotational force on the sides is asking us for a harder bullet.

At rifle speeds (roughly considered 1,600fps+, definitely 2,000 fps+), especially through faster twist rate barrels, we cease to have lead-based alloys that can handle that torque, so the gas checks become pretty much 100% necessary.

With pistols or lower speed rifles, the main asset a gas check brings is that it allows you to shoot alloys that are otherwise softer than ideal for the speeds in question - - such as if you wanted a bullet to expand on impact. In effect, the gas check is making the gun think it's shooting a bullet that's harder than it actually is. If you aren't looking for expansion; have the ability to tweak the hardness of your alloy; have your bullet fit issues understood and addressed in conjunction with a lube or PC that provides an adequate gasket boundary layer, you aren't going to need gas checks at handgun speeds.

You're going to get a lot of good general advice here about where those speed, pressure, and torque limits roughly lie, and that will typically serve you pretty well. If you're chasing the outer fringes of those limits, each gun starts having its own rules, and you'll ultimately have to test the electric fence with your own urine.

[castmiester]

Bigslug...true that, good advice thanks.

[Apple Man]

Very good information from what I am reading. This reinforces concepts of what I have always believed and only have one good friend who casts that understands what I am talking about. (Until I found this forum);)

IMHO, bullet casting successfully is all about matching chamber pressure with the BNH of the boolit. Too soft, leading in front of the forcing cone, too hard yield leading towards the muzzle from gas cutting getting around the lube groove.

Every once in a while when the snow is melting and turns into "corn snow", boolits can be recovered laying on top of the snow with zero deformation and proper obturation is evident as is the rifling marks. Gas cutting is evident in "shiny" bands perpendicular to the lube groove(s).