Compressed Loads and Powder Selection

[mbruce]

When deciding on a powder to use....should you use a powder whose max load is not compressed before using a powder whose max load IS compressed?

For an example.... I have the following:

Bullet:
Barnes .357 125gr XPB (~.724" long) ( ~.310 of bullet is exposed and OAL 1.585" - Barnes website) (so ~ .414" of bullet is seated in case)

Powder Selections:
AA #5 (Max is 11.8gr - #49 --- Max is ~.626" from mouth of case)
AA #9 (Max is 14.0gr -Barnes website -- will p/u powder tomorrow)
2400 (Max is 17.5gr - Alliant website-- Max is ~.239" from mouth of case)

Of the 3 listed powders the 2400 is compressed...so do I use either of the other 2 powders listed since their loads are not compressed? (assume #9 is not compressed....)

I have no other 125gr bullet to compare to the Barnes 125gr...it may be common knowledge that Barnes are longer and therefore the powder choices are limited (if you wish to avoid compression) -- then again compression may not be a big deal if you are within books' load data?? I know some compressed loads are marked in books -- but doesn't really explain the significance other than compressed.

Guess question to this post is is compression a big deal when you STAY within books' load data? if the answer is it depends...then that's just crummy.

 

[redbullitt]

Just going to come down to case capacity. Yeah longer, heavier bullets will protrude into the case more and diminish powder capacity.

Granted you are using pistol rounds as an example...

For me, it really has not mattered much. I do not run any max loads since I have always found a great accuracy node before that. Dont chase the velocity gremlin much myself.
I do like a "full" case with limited air space. When you shake it, it shouldnt make too much noise. My 308 or 223 or 243 accuracy loads are under max, not compressed, but there is not a ton of air space in there. The case will usually be just about "filled." Of course there are exceptions. My 260 rem with h4350 is one. I am getting pressure signs early enough that I still get a good bit of air space AND I am using long 142g pills. Guess what? It will still shoot half minute.

That said, I have never made a consideration of it when choosing a powder. To be perfectly anal, the rifle should choose the powder. This takes more time, but it will result in the "best" load you can make. Some rifles like some powders in certain combos; that is just how it goes. It is going to come down to what shoots well, what you can get, afford, use in other rifles, and what you just plain like.

The load data in the book is not gospel. It is worked up in their rifle under their conditions. It is considered to be safe, but your max may be found at a higher or lower charge, hence work your own load up. Ideally you should be using the same bullet the load data prescribes. If this is not the case, be sure to work up from the lower loads.

 

[[email protected]]

When developing a load thank about what you want from it in terms of velocity and accuracy. You should get higher velocity in the 357 mag with slower powders. Slower powders dont tend to spike fast but burn longer. Im not familiar with loading the barnes but speaking generally the 2400 should work fine and if you dont want a compressed load you can back down on the charge. The acc9 SHOULD give you a higher velocity than the acc5. Since you already have the 2400 try it first. It does seem to me that I did get better results using mag primers with acc9 but i do know that it was not a max charge.

 

[mbruce]

cool -- thanks for your inputs.


I'll call Barnes --their tech support can shed some light on the optimal way to load their little long bullet. 2400 is compressed from the starting load on up..... I just used Max for a hypethetical situation bc I became curious about compressed loads and the dangers or cons associated with them...

I load light and do the typical workup that is routinely discussed on the board....just a different game when my starting loads were compressed -- i've never loaded a compressed load and just wondered if you its best to just avoid compressed loads all together by using another powder...or na, it's no biggie when your within load data...

 

[Walkalong]

na, it's no biggie

This, within reason.

 

[USSR]

When deciding on a powder to use....should you use a powder whose max load is not compressed before using a powder whose max load IS compressed?

For an example.... I have the following:

Bullet:
Barnes .357 125gr XPB (~.724" long) ( ~.310 of bullet is exposed and OAL 1.585" - Barnes website) (so ~ .414" of bullet is seated in case)

Powder Selections:
AA #5 (Max is 11.8gr - #49 --- Max is ~.626" from mouth of case)
AA #9 (Max is 14.0gr -Barnes website -- will p/u powder tomorrow)
2400 (Max is 17.5gr - Alliant website-- Max is ~.239" from mouth of case)

Of the 3 listed powders the 2400 is compressed...so do I use either of the other 2 powders listed since their loads are not compressed? (assume #9 is not compressed....)

I have no other 125gr bullet to compare to the Barnes 125gr...it may be common knowledge that Barnes are longer and therefore the powder choices are limited (if you wish to avoid compression) -- then again compression may not be a big deal if you are within books' load data?? I know some compressed loads are marked in books -- but doesn't really explain the significance other than compressed.

Guess question to this post is is compression a big deal when you STAY within books' load data? if the answer is it depends...then that's just crummy.

Depends. In the case that you have given: a light bullet in a .357 Magnum, I would definitely not use 2400 powder. Oh, it would work, but that powder is MUCH better suited to heavy for bore bullets. I would without a doubt use the AA#5 powder, as it has the burn rate most suited to the load you wish to develop. So, to answer your question, I personally would not use a powder whose max load IS compressed if the bullet is light for bore.

Don

 

[Funshooter45]

Whether or not the powder is compressed at max is not a factor I consider when choosing a powder/bullet combination. Granted, I would rather use a powder that fills the case more than halfway full in a pistol, and at least 90% full in a rifle. It's just easier to see the powder that way. But I have produced some fine revolver loads using fast burning powders that don't even use 1/3 of the case volume.

But that's just me. It might be different because for .357 I only use 158 or 180 gr bullets. If I want high velocities I stick with H110 or AA9 or Enforcer. A lighter bullet will probably prefer a faster powder for good velocity. You just have to try a few and find out what works best, but don't limit yourself to only compressed loads.

 

[Steve C]

The Barnes XPB bullet is an all copper bullet. Due to the lower mass of copper an all copper bullet will have to be longer to have the same bullet weight as a lead bullet.

You should use load data from Barnes for their all copper bullet and not use data for conventional copper jacketed lead bullets as they have different properties that will effect pressure.

 

[mbruce]

You just have to try a few and find out what works best, but don't limit yourself to only compressed loads.

Thanks for the input.... I was more concerned with compressed loads and whether to avoid them or na it's just another part of reloading...sorta speak. In way i was asking should one limit him/herself to only uncompressed loads.

You should use load data from Barnes for their all copper bullet and not use data for conventional copper jacketed lead bullets as they have different properties that will effect pressure.

Yea I e-mailed Ty @ Barnes and he provided new un-released load data for 2400. Their current load data only gives data for #9 and enforcer. (FYI : Barnes is about to publish new data on their website in the next few days) http://www.barnesbullets.com/images/357MagnumWeb.pdf

 

[gamestalker]

I load a lot of compressed loads, and it seems the slower burning powders are more inclined to produce them. An example using .357 mag. for me would be with H110 or 296. That powder is a very slow burning powder for that application. The listed data even with starting loads, is likely producing a compressed powder charge. But, even though the data is safe and SAMMI tested, I can say with certainty, it is producing some rather high working pressures. In my experience, a compressed charge seems to be the norm with slower burning powders, with rifle and handgun.
Another element of interest I've realized with the slow burning powders is, they seem to me to porduce higher end velocities while, maintaining consistent and well managed pressures. Now in this regard, though pressures have been typically consistent and well managed, they are in the higher working range.
My personal desire to load in this manner is because, it satisfies the high velocity criteria I'm seeking, while still producing respectable accuracy at extended distances.
The loading practices I've touched on above and personally engage in, are probably not the norm or average that most hand loader's would desire. FYI, the above hand loading practices will likely produce maximum or near maximum velocities and reoil, and possibly excelerate wear and tear on your firearm.

 

[GLOOB]

Assuming it shoots as good, and the cost of powder is the same, I would prefer the compressed load, if anything. An overcharge is easier to spot. Setback is less likely. The round will fire the same way, whether it's level or pointing up/down.

 

[NCsmitty]

I see that Grafs has the Barnes XPB 125gr at $13.99 for 20pcs and Hornady 125gr XTP at $15.99 for 100pcs.
Are the Barnes with their load issues, worth nearly 5 times more than the great lead core XTP? Are you required to use a lead free?
Just wondering.



NCsmitty

 

[mbruce]

I see that Grafs has the Barnes XPB 125gr at $13.99 for 20pcs and Hornady 125gr XTP at $15.99 for 100pcs.
Are the Barnes with their load issues, worth nearly 5 times more than the great lead core XTP? Are you required to use a lead free?
Just wondering.



NCsmitty

They make great .357 Keychains! no j\k...

They are a one-time buy. I thought they were cool looking because their cavity is
~.2925" deep where as the XTP's cavity is ~.088"

the cavity depth may make no difference...but they look good. I buy MBC lead for every caliber I shoot...I got caught up in the glamour of the bright shiny copper and wanted to splurge once! When my wife finds out she will pull the plug on future splurges on Barnes...

 

[Seedtick]

When my wife finds out she will pull the plug on future splurges on Barnes...

Mayhap you should go ahead and get 2 boxes then.

What was it I read...something like...
it's just as easy to ask for forgiveness as it is for permission.

Seedtick