Jump to content
plumbshotsam

Relative spaces to powder top and bullet base

Recommended Posts

   A question for the old timers and experts:

                 I have been reloading successfully (still have all 11 fingers) for about two years now and have purchased, and read many books, topics, and on line articles on the subject. I actually think I am really getting the hang of it. Currently, I only reload 38 specials, 357 magnums, and 9 mm.  I shoot and reload around 400 rounds each month and it really is all starting to make sense to me. I reload very cautiously with a single stage press, inspecting each and all cases after cleaning, priming, and charging before placing the projectile in the case. I have always noticed that in some loads there is a gap, sometimes sizeable,  between the top of the powder charge and the back of the bullet (most apparent in some 38 special and 357 mag loads) and in others (9mm) the back of the bullet appears to seat right against, or even sometimes appear to be compressing the powder charge.

 

                  All reloading data is very specific about, cartridge overall length, charge weight, bullet weight (even specific brands), and expected pressure inside the cases, taking it to the extreme of sometimes discussing even different barrel lengths and even make and models. Lets not even get started with crimping and it's impact!!!!  My question is, ...is there a specific or approximate relationship to both  (powder top and bullet back) and how does that gap change the dynamics of the load. I respect load data tables and would never alter charges based on visual observations, but this scenario just never quite made sense to me. Is there an optimum relationship or does it not make a difference?

 

                 As an aside, I am relatively new to NJGF but am loving it and think it is a veritable treasure chest of good info on many matters. It is really great to have a local source of good info and expertise. (what is new and great in Montana is not necessarily useful to Garden State residents!!) On a recommendation from a post I started looking at Ruger GP 100's as my next purchase and was lucky enough to bring home a Match Champion today. ...You KNOW I will be at Heritage, Easton Monday morning at 9:00 AM!!!!  (the new baby will get new factory ammo, ....to start!!!)

 

 

                 THANKS TO ALL

 

 

Share this post


Link to post
Share on other sites

You are over thinking it. You have to remember that wthe rounds are horizontal in your mag and gun. It does affect some long cases with lots of powder but that's when they specify a magnum primer to shoot a little extra spark down there.

Share this post


Link to post
Share on other sites

Total aside here, but I shoot every Monday at Heritage too and would like to see your GP. What time do you usually finish shooting? (The wife goes with me most mornings and we never get there before 10.)

Share this post


Link to post
Share on other sites

most of the data is figured by volume of the case.  I am in the process of reloading for a caliber that doesn't have any data on it.  Figure the volume and start from there. 

Share this post


Link to post
Share on other sites

You are over thinking it. You have to remember that wthe rounds are horizontal in your mag and gun. It does affect some long cases with lots of powder but that's when they specify a magnum primer to shoot a little extra spark down there.

 

This is not necessarily correct.  What I am about to say relates to rifle cartridges.

Top reloaders choose a suitable powder that fills about 95% of the case.

There are of course exceptions related to loading data such as compressed loads with certain powders.

Again this relates to rifle cartridges and top accuracy loads. 

I can's see why this wouldn't carry over to pistol cartridges.

Share this post


Link to post
Share on other sites

For handgun cartridges, and almost ALL cartridges it doesn't matter as long as you staying in publish load space.

 

Two reasons why this is so.

 

First, each published load has been tested by the manufacturer of the powder. They know damn well how fast their powder burns, how much gas it generates and how much space it needs, and the decided that the ratios inside the case are such that they wont get sued.  Specially when you get to rifle powders you will see things such as compressed loads (the powders gets squished down inside the case) and in some pistol loads the powder is just a dusting on the bottom of the case (I'm looking at you Titegroup in .45).

 

The second reason is to think what goes on inside a case. First lets assume you are using a somewhat correct powder for the cartridge, not that you filled a rifle case with pistol powder (we'll know from a county or so away, we'll hear it). Lets say you are comparing two powders suitable for .45, Clays and Titegroup.  Clays will damn near fill the case, and TG is so compact you can fit in four charges and still sit the bullet with not compression, but you are using the recommended charges for each. You put your round in the gun, and press the happiness switch.

 

What happens inside the case? The powder starts burning, but does not finish doing so while the bullet is still there, in fact the powder keeps burning after the bullet has left the barrel, thats why we get flash and sometimes unburned powder. Basically it makes MORE room inside barrel to burn more and reduces its own pressure by pushing bullet forward, will still burning. All the burning and pressure don't happen while the bullet is still in there.  Powders have burn rates, some powders burn faster some burn slower, the shape of the powder pellets can make a difference as well. A powder that is tighter packed may burn "slower", with the first bit of burn pushing the bullet out and making room for the rest of it to burn, where a more compact powder may burn more of it self to fill the case with gases to the point the bullet leaves, but it all boils down to first reason, the performance specs for each powder and cartridge are matched to each others. That is why we have load data.

Share this post


Link to post
Share on other sites

Thanks for the lengthy post Vlad!

 

Bottom line follow load data!  Agreed!

 

Some powders (many are listed in load data) are better than others for a given use even though may will work safely.

 

Chet on this...Bullet obduration with lead bullets.

Share this post


Link to post
Share on other sites

So what are you guys using for 223? If I am using h335 at 25 grains with an OAL of 2.220 there is still a lot of room inside.

 

Not saying this will work for you and I accept no liability

 

25gr of W748 or CFE 223 under 55gr BTFMJ.   CCI or Wolf primer various cases seem safe. Crimped at cannelure about COL 2.250 +005 - 0

Share this post


Link to post
Share on other sites

So what are you guys using for 223? If I am using h335 at 25 grains with an OAL of 2.220 there is still a lot of room inside.

And that's fine as long as the charge isn't so small the flash hole is exposed when horizontal. That, in theory, can cause flash over.

 

I've used tac, which leaves a little room, and Varget which is a compressed load, so zero empty space.

 

 

Share this post


Link to post
Share on other sites

This is not necessarily correct. What I am about to say relates to rifle cartridges.

Top reloaders choose a suitable powder that fills about 95% of the case.

There are of course exceptions related to loading data such as compressed loads with certain powders.

Again this relates to rifle cartridges and top accuracy loads.

I can's see why this wouldn't carry over to pistol cartridges.

He is talking basic pistol loads so I can't think of any compressed loads outside of a 9mm that's meant to make major for competitive purposes. Maybe there are some oddball ones but I didnt think pistol rounds had compressed loads.

Share this post


Link to post
Share on other sites

Not saying this will work for you and I accept no liability

 

25gr of W748 or CFE 223 under 55gr BTFMJ. CCI or Wolf primer various cases seem safe. Crimped at cannelure about COL 2.250 +005 - 0

Yeah my loads are working great I thought it was weird with the airspace at first compared to reloading pistol

Share this post


Link to post
Share on other sites

    (the new baby will get new factory ammo, ....to start!!!)

 

 

                 THANKS TO ALL

 

Why?  I have multiple guns that have never seen a factory round

 

feed it the good stuff right from the start -- the hell  with factory ammo -- yours is better

 

I've been reloading for over 20 years -- I remember being surprised when I 1st started about how little a proper charge of bullseye filled a 45 acp case -- never really gave it much thought after that

 

I do know that the more filled a case is the more complete of a powder burn you get --

Share this post


Link to post
Share on other sites

Heavyopp has it right.  No need for factory ammo to start.  Last new caliber (300BLK) the rounds were made from 223/556 brass with bad shoulders or case mouths that were crushed. Trimmed, run through the resizing die, trimmed again for length and loaded. Works great.  Had primers, powder, and heads for other same calibers, cost to make 300BLK rounds, less than .35/ea.

Share this post


Link to post
Share on other sites

            WOW!! You guys are all the best! I am sitting here reading and visualizing this little bitty slug followed by a BIG RED FLASH.

 

       A while back I was at the range and the guy next to me was shooting what sounded and felt like a cannon!! It actually almost physically hurt to be right next to him when he fired, so I would time my vollies to  alternate with his. This was actually the first time I actually stopped and watched what was going on; as he fired I could see the muzzle jump; the ENORMOUS flash at the end of the barrel, the slight blowback around the cylindar and then, obviously feel/hear the report. (I believe it was a 52 cal Smith & Wesson?)

 

      When you talk about the bullet being in motion before all the powder has ignited and possibly being out the muzzle before combustion is complete it really brings all that home. I also have had one more really great realization about powder burn rate. Also, the horizontal positioning of the charge and primer "blowby" is also something that I never would have even thought about if I didn't read about it here. Thanks to all for their responses, I will continue to monitor this thread and watch for other great responses.

 

       As far as , "..the new baby getting factory ammo";  I always like a benchmark; I have a S&W 586 in 6" bbl that reacts completely differently from the 4" bbl 586 that I have rented and fired with white box range ammo you are usually required to buy when renting. I would like to know how the new gun will react/feel with "vanilla" ammo before I drop in a few of my own reloads some probably a bit hotter and some a bit colder. Besides,.......how else do I get cases to reload!!

 

        Hey SOF, I will probably be there until around 10:30, would be great to meet you; I've probably seen you there before.

 

                                 Again, thanks to all.

Share this post


Link to post
Share on other sites

Powder is as fully combusted as it will within 1-2" of barrel travel.

Compressed loads can be very good--simply slow, fluffy powders for the cartridge. Didn't your manuals discuss this? Do manuals discuss anything any more, like COL determination or need for case expansion or taper crimp?

The only benchmark I have is how my reloads work in a gun. Factory ammo? Only if I don't reload for it already.

Never, ever, take short cuts. Always start with the starting load and work up.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

  • Recently Browsing   0 members

    No registered users viewing this page.



×
×
  • Create New...