Velocities w Lubed, Gas Checked Bullet

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I Dont Care About You

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I'm a bit new to cast bullets in rifle cases, so not sure how much velocity I can expect from a conventional lubed / gas checked bullet?

First time out I managed a couple of different loads with a 200gr bullet that went 1635 fps and 1645 fps in a Lee Enfield.
 
I bought them at a gunshow probably 15 years ago. They were in a cigar box. Basically I know nothing about the details of how they were made or what the alloy is or lube. The lube is like nothing I've seen on a commercial cast pistol bullet. I'd describe it as very thick molasses. Its not solid and can be wiped off w a paper towel.
 
I Dont Care About You said:
I bought them at a gunshow probably 15 years ago. They were in a cigar box. Basically I know nothing about the details of how they were made or what the alloy is or lube. The lube is like nothing I've seen on a commercial cast pistol bullet. I'd describe it as very thick molasses. Its not solid and can be wiped off w a paper towel.
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I’d keep them around what you are shooting now for velocity. Wheel weight alloy water dropped or Lyman number 2 alloy can be driven pretty fast. You are going to want to slug your barrel and get a bullet that will be groove diameter or .002 over groove diameter.
 
Fingernail test can give you an idea of the hardness: nice scratch on pure lead vs no scratch on Linotype. Wheel weight is somewhere in between. Not much risk in cranking up the speed until accuracy gets worse. Then you check for lead in the barrel. A good way is to wrap copper or brass filaments removed from a scouring pad and wrap around a bore pad. First check the scouring pad with a magnet to ensure it’s not plated iron. I easily get to 2200 FPS with wheel weight bullets.
 
You can push those 1800-2000fps if they are gas checked and measure .313-.314 if they were sized to .312 or less id stay where you are.

The key to stop leading is to make sure the bullet is bigger then the bore. I want the bullet as over sized as it can be as long as it can slide in a dull pressure fired cases mouth.
 
Evanguy said:
You can push those 1800-2000fps if they are gas checked and measure .313-.314 if they were sized to .312 or less id stay where you are.

The key to stop leading is to make sure the bullet is bigger then the bore. I want the bullet as over sized as it can be as long as it can slide in a dull pressure fired cases mouth.
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This ^^^^^^

Let the throat of the barrel size the bullet.
As a general rule I use the larges bullet that will easily chamber in the rifle. In my 9.3x57 (Jacketed bullets are 0.366") a 0.368" cast bullet will enter the chamber easily. A 0.369" bullet will feel tight when chambering. I size to 0.368".
If I thin the neck of the 9.3x57 brass I can chamber 0.369" easily- every cartridge has to be checked before firing.
I shoot 200 grain cast bullets that are powder coated, then gas check added, and sized with an NOE button size die.
I have given up on slugging the bore as I find that the largest cast bullet that will chamber easily will almost always give the smallest groups.
The cast bullets sized to 0.368" give the same groups (1.5" at 100 meters) as Hornady 200 grain 0.375 sized to 0.368"
 
The long held rule of thumb was that 2000 f/s was the upper limit for greasers.
Your lube may be the old Esso Galena, used in locomotive hot boxes. It was good for handguns and modest velocities in rifles.
Better lubes were required for the higher velocities.

I would suggest that if you're going down the cast bullet rabbit hole, you start powder coating. It has a much flatter learning curve and accuracy at 2400+ is fairly easily obtained. Powder coating has rewritten the rules on cast bullet shooting, and they are still changing.
 
slug said:
the long held rule of thumb was that 2000 f/s was the upper limit for greasers.
Your lube may be the old esso galena, used in locomotive hot boxes. It was good for handguns and modest velocities in rifles.
Better lubes were required for the higher velocities.

I would suggest that if you're going down the cast bullet rabbit hole, you start powder coating. It has a much flatter learning curve and accuracy at 2400+ is fairly easily obtained. Powder coating has rewritten the rules on cast bullet shooting, and they are still changing.
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this^^^^^^^^^
 
I believe in the RPM theory,
i have done load testing and have found this to be true, in my limited testing .... if only shooting at 50 yards or so you might be able to go faster but at 100-200 -300 yards and farther it holds true

Copied From a Cast bullet site
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RPM Threshold barrel twist/velocity chart

RPM threshold twist/velocity chart

I’m posting this at request for an easy reference to see the velocity range where the RPM threshold will most likely be found based on the twist of the barrel.

The RPM threshold is that point where accuracy begins to deteriorate when the RPM is sufficient to act on imbalances in the bullet in flight to the extent the bullet begins a helical arc in flight or it’s flight path goes off on a tangent. It is best noted when working up a load as velocity increases flyers begin to happen. Then as velocity is further increased the total group size increases sometimes to the point some bullets fly so far off they miss the target. A further indication the cast bullets at or over the RPM threshold is (or some of them in a load that is on the edge of the RPM threshold) the non linear dispersion of the group size as range increases.

Let us keep in mind the RPM threshold most often falls in the 120,000 to 140,000 RPM range with regular lube groove cast bullets. Exactly where the RPM threshold will be in fps depends on numerous factors; alloy, bullet design, fit, sizing, lube, GC’d and seated square, powder burning rate and the length of the barrel, etc. The RPM threshold may be lower than 120,000 RPM by careless casting and loading techniques or when using very soft alloys with very fast burning powders. Conversely, the RPM threshold can be above 140,000 by careful casting and bullet selection and preparation along with careful accuracy enhancing loading techniques, especially those for cast bullets at high velocity such as using slow burning powders that ignite easily and burn efficiently at lower pressures. The trick is to get the cast bullet to exit the muzzle as balanced as possible with as little deformation to it during accelleration. The more balanced the bullet is and the closer the axis of rotation coincides with the center of mass on exit from the muzzle and during flight the more accurate the bullet will be and thus, the higher the RPM threshold will be.

The RPM threshold is not a set “limit” of RPM or velocity. Best accuracy will be just under the RPM threshold or lower. Useable accuracy can be had above the RPM threshold if the ranges are not long and the accuracy requirement is not small. Keeping .223 cast bullets on a silhouette target out to 200 yards for example or keeping hunting cast bullet accuracy at say 4 moa if the max range to be used is 50 – 100 yards.
Again; the RPM threshold will generally be found between 120,000 to 140,000 RPM with regular commercial cast bullet designs and loading techniques most cast bullet shooters use.

In the chart below I’ve computed the fps for various common barrel twists for 120,000 and 140,000 RPM. For other twists in between anyone shouldn’t find it too difficult to interpolate. These fps figures should give you an idea in what fps range your loads, as you work them up, will probably bump into the RPM threshold and when accuracy will probably begin to deteriorate. Some pundates will crticise this chart saying they, or someone else, gets accuracy above the figures in the chart. For those who understand how to push the RPM threshold up with higher velocity cast bullet loads that can indeed be the case. However, as mentioned, the chart is for the majority of cast bullet shooters who do not care to push the RPM threshold up but simply want to understand where and why accuracy will probably deteriorate with their regular cast bullet loads. This chart was done for them.

RPM……….120,000……….140,000

Twist……….FPS…………..FPS

7”…………1166…………..1361

8”………….1333…………..1555

9”………….1500…………..1750

10”………...1666…………..1944

11”………...1833…………..2139

12”…………2000………….2333

14”…………2333………….2722

16”…………2666………….3111

18”………….3000…………3500


And if you look at the 10 twist =2000 fps +- is max

Also bullet length plays a factor
 
I Dont Care About You said:
I have not heard anyone suggest that PC bullets should be pushed past 2000 fps.
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In my post from Nov 9, 18 on my new mould, I reported 2424 f/s from my .30/30 with acceptable accuracy.
While the accuracy wasn't great, it was remarkable with the velocity attained.
It goes to emphasize that a modest improvement in performance, both velocity and accuracy, requires a significant increase in care in loading and bullet selection.

Our American cousins have reported higher velocities and better accuracy in their powder coated loads.
As I have mentioned before, powder coating has changed the rules for cast bullet shooting, and the change is ongoing.
 
Is much about bullet performance in flight that is almost counter-intuitive - my Dad was always concerned about the "munched up" soft point bullet noses for his 30-06, that had been cycled through his P17. A Bench Rest shooter acquaintance tells me to go ahead and deform bullet tips and shoot them - won't see a whole lot of change in group size at 100 yards - but even slight dings on bullet rear end - especially at the edges - that user can not see on a loaded cartridge - has huge effect on group size.

There is several boxes of .338" Nosler Accubond here - likely older or original stock - as I open them, usually find a few "tips" in bottom of the box, and some bullets missing those tips - and I use them for pressure test series, or to roughly sight in new-to-rifle scope - seem to work fine for that - no tip - so weight slightly different (?) - I have never shot a critter with one, but I suspect that performance after impact is not going to be much different - I proved to myself - at least to 100 yards, that the performance before impact is not altered very much.

I have not looked into the above "RPM Theory", but is a thing that I suspect many do overlook - 1-10" twist, 2400 fps at muzzle - that bullet is rotating like 173,000 rpm upon exit. What is acting on that bullet in air to slow down that RPM? Not really so much - so impact at 100 yards - bullet will have a forward velocity, but also like 150,000 rpm - so a bullet found against far side hide - not only slowed to 0 fps, but also slowed to 0 RPM - between point of impact and its final resting spot.
 
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There was an article by John Barsness - somehow, he got the use of a Juenke testing machine - was a way to check bullet's balance before you shot it. He would sort various boxes of bullets on that machine - sort them into well balanced and not so well balanced - he was abe to get significant, repeatable results to show that the better balanced bullets made smaller groups - he presumed they "flew straighter".

I do not know why that Juenke machine is not commonly available - likely because that Vern Juenke guy has passed on. Or maybe lack of interest among shooters? Better marketing by people selling other stuff? I seem to recall Barsness noting a significant improvement in bullet balance for various bullet makers, once they acquired and used that Juenke machine to set up their bullet making process - I would have thought casters and powder coaters would be interested to do the same?
 
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Potashminer said:
Is much about bullet performance in flight that is almost counter-intuitive - my Dad was always concerned about the "munched up" soft point bullet noses for his 30-06, that had been cycled through his P17. A Bench Rest shooter acquaintance tells me to go ahead and deform bullet tips and shoot them - won't see a whole lot of change in group size at 100 yards - but even slight dings on bullet rear end - especially at the edges - that user can not see on a loaded cartridge - has huge effect on group size..
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Correct. The reason nose damage doesn't affect accuracy is because any asymmetrical flow is averaged out around 360 degrees as the bullet spins.

The reason base damage does affect accuracy is due to asymmetrical gas flow around the bullet at the instant it leaves the muzzle. Asymmetric flow at this point gives the bullet a "kick in the ass" on one side, which causes it to wobble. This is the same reason we want a perfectly symmetric and undamaged crown.
 
Potashminer said:
There was an article by John Barsness - somehow, he got the use of a Juenke testing machine - was a way to check bullet's balance before you shot it. He would sort various boxes of bullets on that machine - sort them into well balanced and not so well balanced - he was abe to get significant, repeatable results to show that the better balanced bullets made smaller groups - he presumed they "flew straighter".

I do not know why that Juenke machine is not commonly available - likely because that Vern Juenke guy has passed on. Or maybe lack of interest among shooters? Better marketing by people selling other stuff? I seem to recall Barsness noting a significant improvement in bullet balance for various bullet makers, once they acquired and used that Juenke machine to set up their bullet making process - I would have thought casters and powder coaters would be interested to do the same?
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Back in the 60's my old man used a devise to test bullet concentricity. It was plain simple, a glass mirror about 18 inches long. He would level the mirror side to side and raise one end to create a rolling slope to the long end. He had a straight center line etched into the glass. he would start every slug he purchased at that time centered on that line and let it roll to the bottom. If a bullet deviated from center at the bottom of the roll, that bullet went into the "practice pile" if it rolled straight it went into the "gopher shooting & hunting pile.

That was back when manufacturing methods weren't up to todays standards and I can remember lots of bullets rolling off-center...the other thing I remember is that he almost eliminated "group fliers" from his hunting pile so that simple tool must have had merit.
 
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