Reading the pet loads of top shooters

Question,
Why do so many increase powder gn with a lighter bullet  for only 25 yards further ?
example lead 200 gn SWC vs 185 gn JHP.
Thanks
Ron

Ballistics.

Read up on it, it is very interesting.

My thought is that we needed a little more velocity & spin to keep the bullet stable.
It may also help to flatten out the flight path, reducing the amount of adjustment needed to get to the middle.

I may be wrong once again so take this with a spoonful of salt.

Ballistics is a interesting subject I once gave a lecture on it.  Don

STEVE SAMELAK wrote:My thought is that we needed a little more velocity & spin to keep the bullet stable.
It may also help to flatten out the flight path, reducing the amount of adjustment needed to get to the middle.

I may be wrong once again so take this with a spoonful of salt.

OK, then why not run the same gn with both styles of bullet ? Or will it overpower the SWC at the shorter distance and kill some accuracy ?

Short answers.
1.JHP are more accurate but need more powder to not hang up in the barrel.
2. L-SWC bullets can be loaded much lighter and not hang up in the barrel.
3. Lighter recoil preferred for timed and rapid fire and accuracy not as important.

Thanks for the short answers. That is what I was looking for. A reason to not load the same gn of powder for the two types of bullets at two distances.
Is this possibly why L-SWC HP are now gaining popularity ?

No idea. I have never used L-SWC HP. Never found the need to try.

Len

The difference in powder to leave the barrel can be measured in 0.1gn, and is much less than 1.0gn. Just the primer will get the bullet 1-3" down the barrel.
One reason can be to not have to adjust sights.
Main thing is you need your most accurate load at 50 yards and you need a comfortable load for 25 yards.
As bullet weight goes down, the amount of powder you need goes up.
If you want the fine details, you should read what the masters wrote.

The reason for upping powder a tad when loading a lighter bullet is to give the same impulse to the operating parts of the pistol ( slide and barrel) with both loads. 

Impulse is momentum basically which is bullet mass times velocity.
Let's say you have a load with a 200 grain bullet at 720 fps which functions fine. If you find a 160 grain bullet and want to try it, you'll need to load it up to 900 fps to get the same functioning. 

Jacketed are loaded hotter because jacketed have higher resistance through the barrel.

OK, In general here are some starting items. Someone can always find an exception to the general, but:


1.  We are generally loading with smokeless / progressive powders.  These powders generally burn progressively faster as the pressure increases to a certain point.  How fast the peak pressure is reached in general determines what we call a "fast" or "slow" powder.  Pistols generally use very fast or fast or medium powders. 
2.  The available case capacity after the bullet is loaded will generally have as large an effect on the pressure as changing the amount of powder.  A small charge of fast powder in a smaller space can have a higher pressure than a larger amount of powder in an even larger space.
3.  Lead bullets generally take less powder for a specific velocity than jacketed.  Friction, bore fit, etc. are in play here as well as case volume available for the powder after the bullet is seated to its proper depth.  
4.  Heavier, longer bullets generally create less space in a case than lighter, shorter bullets if seated to similar overall lengths.  
5   Just because the bullet gets out the barrel does mean it will be accurate as any specific yardage.  Achieving bullet stabilization and velocity inconsistencies from small charges or variations will be more pronounced for very light loads.  Of course these will have minimum recoil, but without accuracy who cares.  In general and up to a point, faster loads (especially with jacketed bullets up to supersonic speeds) can be more accurate, but will also generate more recoil.  You can't get away from Mass 1 times Velocity 1 = Mass 2 times Velocity 2. 

For example; I use 180 gr. Oregon Trail at the short line and 200 gr. Oregon Trail at the long line.  With the same charge of 3.85 gr. of VV 310, the heavier bullet has a faster velocity when they are both seated to the same OAL.  This is the result of change in available case capacity since the 200 gr. bullet takes up more internal volume.  I get exceptional accuracy at 50 yards with the 200 gr. bullet and much less recoil at 25 with the 180 gr. bullet due to the lower velocity and lower weight at an acceptable accuracy level.

Good stuff. Thank you gentlemen and I appreciate you taking the time.
I now have a better understanding from reading your replies.
Ron
PS: I just looked up Oregon Trail and no 185gn SWC listed. 180 and 200 ?

Sorry, yes they are 180 gr.  Just a typo.

It is a good thing we don't have to meet PF, power factor, like is a lot of the shooting sports.  Don

Magload wrote:It is a good thing we don't have to meet PF, power factor, like is a lot of the shooting sports.  Don

Ah, but when the dinosaurs roamed the earth, we were required to shoot 230 grain, factory hardball .45 ACP, in CMP matches with our un-scoped and little modified 1911 pistols. We were even issued it on the firing line.

CR10X wrote:Sorry, yes they are 180 gr.  Just a typo.

Thanks

As to the LSWC HP  I find them to be  second only to the Nosler 185 JHP in accuracy.  Lighter load due to the lead and they cost less.. what's not to like...

I don't know why other increase powder for 50 yards. Me a few friends and Adam when he was home didn't increase powder for 50 yards, we did reduce powder for 25 yards. We tested accuracy at 50 and adjusted powder to give the best accuracy. For 25 lower charge didn't change the accuracy or enough to worry about but the reduced charge was lighter recoil. Not all bullets of the same weight but different manufacturers will have the same accuracy with the same powder charge. When Adam started shooting great scores we stopped shooting lead and shot only jacketed. I ordered the bulk pack from Midway of 500 in Remington and Winchester. We were using Remington but Midway didn't have 1000 185gr Remington so I got Winchester. Remington shot great with the load we tested for it at 50 yards but when we tried Winchester they shot lousy! I did get more Remington but at the rate Adam was shooting at the time we ran out. Waiting for the next batch Adam adjusted the charge and the Winchester shot as good as the Remington. Entered the info into our reloading notebook and we were able to switch between the 2 when ever one was not available.
 So I'm thinking most don't add for 50 yards but lower the charge for 25 yards. Later I gave up lowering the charge and shot the same at 25 because it was a pain in the butt to remember to change the rounds used when changing distance.

I just scored 700 Winchester 185 FMJ SWC in the little boxes of 100.  What charge gave you the best accuracy?

4.2 BE or 4.3 WST. Remember Full Jacketed need to be loaded a little hotter then lead to be safe.

Len

The RR test I ran on 185gr Zero JHPs shower 4.2 of BE gave the best groups at 50yds.  I shot 3.9, 4.0, 4.1. 4.2 4.3 and 4.4grs.  As the grains increased the size of the groups decreased till 4.2 and then started opening up again.  I shoot 3.8grs under a 185gr Zero HPSWC for the SL but like the idea of having just one load for both lines.  I don't shoot many matches so that would work out good and just shoot the HPSWCs for practice.  Don

Look at it this way:
We develop our long line recipe for accuracy.
Some folks REDUCE their load on the short line because recoil management is more important to them and sufficient accuracy is so much easier to achieve.

So I find that your question is probably inverted.

Develop your long line load to deliver the best accuracy that your gun can deliver. If you don't like the recoil of that ammo on the short line, then develop a softer load that works for you.

Bingo!

Rob Kovach wrote:Look at it this way:
We develop our long line recipe for accuracy.
Some folks REDUCE their load on the short line because recoil management is more important to them and sufficient accuracy is so much easier to achieve.

So I find that your question is probably inverted.

Develop your long line load to deliver the best accuracy that your gun can deliver. If you don't like the recoil of that ammo on the short line, then develop a softer load that works for you.

Gotcha,
As I improve I should be able to recognize more of this as it refers to loads and bullet weights.
Thanks Guys.
Ron

Yes, most shooters develop a good 50 yard load and then reduce the charge to get less recoil at an acceptable accuracy for 25 yard (TF / RF).  Some even use jacketed at 50 and LSWC at 25. 

I developed my load for 50 yards using the 200 gr Oregon Trail LSWC.  Then, rather than trying to adjust the powder, I just replaced the 200 gr bullet for the 180 gr SWC just to see how it would work.  Got less recoil and good accuracy (almost as good as the 200 gr bullet when tested at 50 yards so they can be used in pinch at the long line).  The big benefit is I don't have to change any other settings on the press or powder measure.  

CR