CAST vs JACKETED: EFFECT ON STANDARD DEVIATIONS?

[45MAN]

RELATED TO AN ONGOING THREAD BY SIXSHOT RE THE GARMIN CHRONOGRAPH IS THE EFFECT OF STANDARD DEVIATIONS ON ACCURACY, ESPECIALLY IN REVOLVERS AT LONGER DISTANCES, SAY 100 OR MORE YARDS.

JUST A "feeling" I AM GETTING WITH ALL THE CHRONO'ing I HAVE BEEN DOING WITH MY GARMIN, AND WHAT I AM "thinking" IS THAT IN REVOLVERS CAST BULLETS WILL USUALLY GIVE HIGHER SD's THAN JACKETED BULLETS. WHAT DO YOU GUYS KNOW, THINK AND/OR BELIEVE? DON'T GET ME WRONG, I AIN'T QUITTING ON CAST BULLETS, ESPECIALLY FOR LOADS FOR MY BELT GUNS AND USE USUALLY NOT MUCH OVER 50 YARDS. 

[longoval]

I have found that weight variation of commercial cast bullets is much higher than that of jacketed bullets. That of course will lead to higher SD/ES on chronos.

[ezekiel38]

PICs it is the gallery!

[45MAN]

Sept 9, 2024 16:47:41 GMT -5 ezekiel38 said:

PICs it is the gallery!

? ? ? ?

[bigbrowndog]

I would also think that bullet hardness of a cast bullet could effect the SD more so than a jacketed bullet. The jacketed being more consistent.

Trapr

[bigbore5]

I would think it depends on many factors. Cavity consistency in the mold. Casting techniques. Constant mold and alloy temps. Alloy used and it's homogeneity. A lot to get just right with cast bullets.

Jacketed must also be very consistent to be accurate.

[sixshot]

All the above is true but not always. If you take the time to weigh each cast bullet & sort them really close then I think you can equal ES & SD with cast compared to a jacketed bullet but for me at least it's not worth it because I can't shoot the difference. I always try to keep my shots to iron sight distance but do sometimes take a longer shot & also sometimes use a scope as I did on the elk last Thursday. That wasn't a cast bullet but I think I would have made the same shot with cast.

Dick

[sharps4590]

FWIW, I always get lower numbers, across the board, with cast bullets BUT, I cast my own and weigh every bullet and watch my alloy like a hawk. If you put good, real black powder loads under that cast bullet, in a good rifle it's rare all numbers aren't single digit, except velocity, obviously.

[leftysixgun]

I don’t weigh each bullet for consistency. I haven’t played with jacketed much at all. I have shot some really low ES/SD with cast bullets. Mostly using big bore cartridges, using HS-6 and Fed 155 primers.
My go to load for 45colt is MiHa 454-640, 10.0gr of Power pistol , Rem 2 1/2, and Starline case….another lower ES/SD load.

I tend to get my wider spreads with heavier magnum loads with H-110.

[45MAN]

QUESTION: SAME STRAIGHT WALL REVOLVER ROUND LOAD IN A REVOLVER AND IN A CLOSED BREECH CONTENDER OR ENCORE, WHICH WILL HAVE LOWER EXTREME SPREADS/STANDARD DEVIATIONS? IF IT EVER QUITS RAINING AROUND HERE, AND I CAN GET BACK TO MY RANGE ON THE RIO GRANDE, I HAVE SEVERAL LOADS (JACKETED AND CAST) THAT I CAN COMPARE IN REVOLVERS vs A CONTENDER AND A 10" RPM XL.

[45MAN]

Sept 10, 2024 7:34:19 GMT -5 leftysixgun said:

I don’t weigh each bullet for consistency. I haven’t played with jacketed much at all. I have shot some really low ES/SD with cast bullets. Mostly using big bore cartridges, using HS-6 and Fed 155 primers.
My go to load for 45colt is MiHa 454-640, 10.0gr of Power pistol , Rem 2 1/2, and Starline case….another lower ES/SD load.

I tend to get my wider spreads with heavier magnum loads with H-110.

WITH THE "heavier magnum loads with H-110" IS WHERE A HEAVY UNIFORM CRIMP REALLY COMES INTO PLAY.

[leftysixgun]

Sept 10, 2024 7:53:52 GMT -5 45MAN said:

QUESTION: SAME STRAIGHT WALL REVOLVER ROUND LOAD IN A REVOLVER AND IN A CLOSED BREECH CONTENDER OR ENCORE, WHICH WILL HAVE LOWER EXTREME SPREADS/STANDARD DEVIATIONS? IF IT EVER QUITS RAINING AROUND HERE, AND I CAN GET BACK TO MY RANGE ON THE RIO GRANDE, I HAVE SEVERAL LOADS (JACKETED AND CAST) THAT I CAN COMPARE IN REVOLVERS vs A CONTENDER AND A 10" RPM XL.

That would be interesting to see the results.

[leftysixgun]

Sept 10, 2024 7:57:13 GMT -5 45MAN said:

Sept 10, 2024 7:34:19 GMT -5 leftysixgun said:

I don’t weigh each bullet for consistency. I haven’t played with jacketed much at all. I have shot some really low ES/SD with cast bullets. Mostly using big bore cartridges, using HS-6 and Fed 155 primers.
My go to load for 45colt is MiHa 454-640, 10.0gr of Power pistol , Rem 2 1/2, and Starline case….another lower ES/SD load.

I tend to get my wider spreads with heavier magnum loads with H-110.

WITH THE "heavier magnum loads with H-110" IS WHERE A HEAVY UNIFORM CRIMP REALLY COMES INTO PLAY.

Yes, I do use a heavier crimp (Redding Profile crimp die) with the heavier cast and H-110 loads, but still get wider ES/SD numbers. But, the groups are good.

[contender]

I'm one of the nuts who has always wanted my cast bullets to be as good as I can make them. I prefer consistent ammo as much as I can,, because I know that the "loose nut behind the trigger" can screw up a lot. So I've chased low SD, ES & very consistent ammo a long time. And I do weigh & sort my cast bullets. I keep them in 1.0 grn batches. I guess it comes from long ago,, reading something Rick Jamison wrote on bullet performance, when combined with very precise loading techniques. I try & eliminate as many mechanical errors as I can,, because the human factor is the weakest link. Lord knows I'm weak enough there.
So I've chased the concept of "perfect" ammo.
I know the gun & the ammo can easily exceed my abilities,, but I'm proud when I get a truly great load. I know that it may not be noticeable at all on a deer or whatever,, but I like to know that if I miss, or whatever,, it's MY fault,, not the gun or ammo. I'm smart enough to know that even the gun or ammo can have limitations as well.

I know I do more than most when it comes to my cast ammo,, but it's also pleasurable when I can make my stuff better than what others may purchase. And when the ammo is very consistent,, and I do my part,, when the stars, moon, and planets align,, it brings a big smile when I see the results.

SD & ES are ways we humble handloaders can measure our results. And I do believe it makes a difference in the performance.

[sharps4590]

Sept 10, 2024 9:14:53 GMT -5 contender said:

I'm one of the nuts who has always wanted my cast bullets to be as good as I can make them. I prefer consistent ammo as much as I can,, because I know that the "loose nut behind the trigger" can screw up a lot. So I've chased low SD, ES & very consistent ammo a long time. And I do weigh & sort my cast bullets. I keep them in 1.0 grn batches. I guess it comes from long ago,, reading something Rick Jamison wrote on bullet performance, when combined with very precise loading techniques. I try & eliminate as many mechanical errors as I can,, because the human factor is the weakest link. Lord knows I'm weak enough there.
So I've chased the concept of "perfect" ammo.
I know the gun & the ammo can easily exceed my abilities,, but I'm proud when I get a truly great load. I know that it may not be noticeable at all on a deer or whatever,, but I like to know that if I miss, or whatever,, it's MY fault,, not the gun or ammo. I'm smart enough to know that even the gun or ammo can have limitations as well.

I know I do more than most when it comes to my cast ammo,, but it's also pleasurable when I can make my stuff better than what others may purchase. And when the ammo is very consistent,, and I do my part,, when the stars, moon, and planets align,, it brings a big smile when I see the results.

SD & ES are ways we humble handloaders can measure our results. And I do believe it makes a difference in the performance.

I got into weighing each bullet into 1 grain lots when I was seriously into BPCR games.  It makes a difference.  I have one rifle that, when I was 20 years younger and the red gods were smiling, would shoot MOA at 600 yards with my bullets, 62 grs. of GOEX Cartridge and Federal 215 primers.

Honestly, unless I KNOW I'm going to be shooting long range with a batch of loads, for revolvers I usually don't weigh them.  Those intended for 100 yards plus ALWAYS get weighed.