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Load Develpment Primer

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mspingeld
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Post by mspingeld 4/2/2022, 10:36 am

Looking for a brief introduction on how the different variables, i.e. OAL, crimp, charge come together in developing the best load for a particular gun/projectile. How important is using a chronograph? Is there an ideal muzzle velocity for a given projectile and when changing one of the other variable do you adjust something else to maintain that ideal velocity? Is that "ideal" velocity independent of the gun? e.g. If I find that a 185 grain swaged hollow point lead bullet is most accurate around 750fps in my 45 with a slide mounted Aimpoint, and then I decide to try it in another gun with irons or a frame mounted dot, would I change a variable to maintain the accurate 750fps?

Here's what I think I know: Seating deeper reduces volume and, thereby increases pressure and velocity. Same with crimping tighter. More powder also increases velocity. Different powders have different burn rates and, obviously also affect pressure and velocity. All variables have strict limits for safety.

Try to keep it simple. I'm not too bright Load Develpment Primer Icon_smile

mspingeld

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Post by oso 4/3/2022, 8:12 am

IMO to many variables to even see the difference. When I do load development for long range precision rifle I do use a chronograph and try to keep the ES and SD as small as possible, but I don't think most shooters can tell the difference on target unless using a F class or benchrest front heavy rest and rear bag. You would have to shoot free recoil to see the difference.

I believe the same is true shooting pistol ammo at 25 and 50 yds. I don't most shooters are good enough to see a difference on target. I would think the barrel would need to be in a barrel vise with all other variables removed to see the difference.
oso
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Post by bruce martindale 4/3/2022, 8:52 am

Mike, it isn't benchrest pistol but your understanding is correct.

Ammo has to function the pistol. This sllows for some spring and charge combination. Twist calculations show stability at a wide velocity range for the 1911 but as always some things are better than others. The issue with both low speed and high (heavy recoil) is shootability.
Low speed is easier on the mind but subject to trigger induced motions. 

Almost anything at 730 fps will work well. Spend your effort on getting a good consistent trigger control and grip.

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Post by Chase Turner 4/3/2022, 4:03 pm

mspingeld wrote:Looking for a brief introduction on how the different variables, i.e. OAL, crimp, charge come together in developing the best load for a particular gun/projectile.

1) How important is using a chronograph?

2) Is there an ideal muzzle velocity for a given projectile and when changing one of the other variable do you adjust something else to maintain that ideal velocity?

3) Is that "ideal" velocity independent of the gun? e.g. If I find that a 185 grain swaged hollow point lead bullet is most accurate around 750fps in my 45 with a slide mounted Aimpoint, and then I decide to try it in another gun with irons or a frame mounted dot, would I change a variable to maintain the accurate 750fps?

Here's what I think I know: Seating deeper reduces volume and, thereby increases pressure and velocity. Same with crimping tighter. More powder also increases velocity. Different powders have different burn rates and, obviously also affect pressure and velocity. All variables have strict limits for safety.


1) It probably isn't important in the way you may think in terms of accuracy nodes; however, there is a link to a post with a comment from jmdavis that indicates that at least some folks have found accuracy nodes using Bullseye powder, and it sounds like they put in the right number of shots to come up with a meaningful answer. But, let's pretend that there aren't accuracy nodes for powder in the 45, though that seems far from settled. A chronograph can absolutely help you determine how much force is being imparted to the gun. Why is that important? Well, if load A is running 775, and load B is running 750 (both on average), the question naturally arises- can you feel the difference? I'm not sure many can. 

But what you may need to know, so that you have confidence in your equipment, is that your load is working as expected, especially when changing from one jug of powder to another of the same brand, but different lot. You can get skunked on gun function if you are running on the far end of functioning due to powder velocity variance from the manufacturing process.

2) Not in my experience. It's more important, after settling on a load that you know is accurate in your platform(s), not to deviate from your "lot" of materials or technique. There may be a little bit of difference in terms of FPS from small pistol to large pistol primers, but I chrono'd some similar loads with the difference being primer size, and I don't believe it was statistically significant in result for velocity, and I don't believe the group size was any worse than average for the gun. Sample size is small on that claim, I'll admit.

3) No. At that point, it's more about making the gun function and potentially finding the new zero in the new gun. If after finding the new zero you notice that the group isn't as tight as it was in the other platform, only then would you start to wonder about what to change; and you are probably better off examining powder weight than any other variable, all things being equal, at that point.

The rest is certainly true. After finding a load that you know is accurate from testing at 50 yards, the next most important thing is gun function. 

You'll note I didn't discuss "feel". While the chronograph generally informs you about your reloading process, I'm of the belief that swaged bullets can go slow, cast can sometimes go slow, but definitely can go fast, and jacketed can go med. fast to lights out as a general axiom. More importantly; I think the object of the 45 load development for this sport is to find the lowest velocity that will hold to your accuracy standard at 50 yards. Any higher and you needlessly beat yourself up, which costs points in fatigue, and fatigue will induce sloppy process.

Hope this helps,
Chase

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Post by sharkdoctor 4/3/2022, 4:52 pm

Long, long ago, in a previous century, when I first started to shoot Bullseye, my mentor told me to use a 200 gr. 45 semiwadcutter bullet with 3.8 - 4.0gr of Bullseye powder.  Over the decades, I have chronographed, crimped, chamfered, trimmed and Ransom Rested loads.  I trained, practiced and went from Marksman to High Master using, you guessed it, 3.8gr of Bullseye with a 200gr bullet.  Read recommendations on this site for optimum loads (notice I did not say "best"), pick one based on how much you want to spend and get to the range!

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Post by mspingeld 4/4/2022, 7:03 am

Great info, thanks to all! OK, I left out reliability. I assumed that was paramount and yes, I know what happens when I assume.

Now, look at my post in a different light. 38 special wad-cutter accuracy at 50 yards. (just got a new, never-fired S&W 52-2! Very Happy )

What I think I'm hearing is the chrono is not that important and the simple strategy would be to ladder some loads, ransom or bench rest for accuracy and call it a day. I'll start with 2.7 Bullseye (cause I have some), Zero 148gn HBWC (cause research said this was the best bullet style to use), mild roll crimp (1/2 turn with a Lee FCD) and seated flush??? (I've heard flush, slightly below case mouth and slightly above). Then I'll try some 2.8 and maybe 2.9. Best group wins. Done and done.

Note: For 45 I normally use swaged for the short line loaded soft (3.9 of N310) and JHP for 50 yards, a bit hotter (4.5 of N310) although lately, with JHP hard to get, I started using the short line load at 50. If I do my part, they're tens but I think I could tighten up the long line by loading a little hotter for outdoor slow fire, say 4.1 or 4.2. I'll save the JHP I have for service pistol matches.

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Post by Slamfire 4/8/2022, 9:06 am

oso wrote:IMO to many variables to even see the difference. When I do load development for long range precision rifle I do use a chronograph and try to keep the ES and SD as small as possible, but I don't think most shooters can tell the difference on target unless using a F class or benchrest front heavy rest and rear bag. You would have to shoot free recoil to see the difference.

I believe the same is true shooting pistol ammo at 25 and 50 yds. I don't most shooters are good enough to see a difference on target. I would think the barrel would need to be in a barrel vise with all other variables removed to see the difference.

I agree about the inability of shooters to hold tightly enough to see differences. However, humans are pattern seeking animals and "see" patterns that don't exist. Humans also "see" what they want to see, hence the vast majority are using three shot groups as a standard of accuracy and consistency, because it is easy to randomly shoot a good three shot group.  Denial is intrinsic to human behavior.

Clark Custom Guns in Louisiana has a 50 yard tunnel in which they test their finished products

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They do see variations in 22lr ammunition in both their custom rifles and pistols. The gunsmith I talked to said the best 50 yard ten shot group that he had shot out of a M41 was four tenths of an inch, the average M41 shoots around three quarters to one inch. The NRA 50 yard target has a 1.7 inch diameter X ring, and a 3.36 in diameter ten ring. Clark's guarantee is their 22lr pistols will hold the X ring.



Heck, cheap CCI STD Velocity will hold the ten ring of a smallbore target at 50 yards with a rifle.



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 I can hold well inside the X ring of a 50 yard pistol target with a rifle, using a bench but I am struggling to keep them all on the repair center off hand with a pistol. I am therefore not going to see the inaccuracy due to rimfire ammunition at distance. I am also quite sure, if I had a 45 ACP rifle, I would see variations at 50 yards due to something ammunition related, but not in a handgun. If the ammunition is horribly inaccurate I might figure out something is wrong, but, maybe not!



It is my opinion that reliability of function is the highest priority in 2700 Bullseye Pistol. Good accuracy with perfect function will result in higher scores than perfect accuracy with the occasional malfunction. Alibi's are score killers.



Along with flinching!

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