The web's most comprehensive user-interactive handloading database! Find the loading data created by handloaders, for handloaders, post your pet loads, or access and develop your own online loading database with our LoadNotes personal handloading database software. This feature, unique in its concept and intuitive in it's data presentation is fast to access, superbly organized and comprehensive in scope.Our online forums for questions and answers on many shooting and outdoor related topics. A dynamic, active, and well-informed resource for your enjoyment and interaction. Our most used resource on this website! Come share the experience with us!
» Advanced

Go Back   Shooters Forum > Handloading > Handloading Procedures/Practices
Register FAQ Members List Donate Calendar Search Today's Posts Mark Forums Read



Reply
 
LinkBack Thread Tools Rate Thread Display Modes
  #1  
Old 04-30-2007, 06:26 AM
Beartooth Regular
 
Join Date: Feb 2004
Location: LA
Posts: 109
Handloads that duplicate M193 for .223?


Registered Users do not see the above ad.


I'd like to load rounds that mimic the mil-spec M193 55gr FMJ catridge. I know that 5.56mm NATO cases are built stronger than .223 brass to handle higher pressures, but since my brass is a mixed bag, what would be a good load to use in both .223 and 5.56 brass. I'm using Hornady 55gr FMJ bullets. What powder and load should I use?

These are for use in my AR's and are just for plinking.
Reply With Quote
  #2  
Old 04-30-2007, 07:34 AM
Beartooth Regular
 
Join Date: Jul 2005
Location: Jacksboro, TX
Posts: 179
Mike,
Here's a load I use in my AR..
25.0g AA2230, Fed small rifle primer all under a 55g PSP bullet. This is a good load that is clean burning and fairly accurate ( I use the cheap bulk bullets from Remington). I cant say this will duplicate the Mil-spec loads, but it works great for me. I dont have access to my notes right now or I would include velocity readings I get with this load, if you want it, let me know and I will post it for you. I did notice that when I went up to 25.5g, the velocity actually decreased a bit, maybe something to do with the gas operation???
Good luck with it.
JR
Reply With Quote
  #3  
Old 04-30-2007, 10:26 AM
unclenick's Avatar
Super Moderator
 
Join Date: Jan 2005
Location: Hilliard, Ohio
Posts: 10,798
There exists no load that will mimic military performance in mixed commercial and military cases. To try to find one presents some potential danger of high pressure. For a given load, the less powder space, the higher the peak pressure. As a result, a load that reaches a certain peak pressure and velocity in one type of case will not reach it in the other. In reloading, unless you are using a load well below safe pressure maximums in all your cases, you must work the load up for each individual component brand involved.

This is why you should not trust incomplete load information. It should include primer, powder charge, case brand, bullet, and cartridge overall length. Even then, if your rifle's throat is significantly shorter than the one the load was developed in (commercial .223 chamber rather than a NATO chamber, for example), you still can get over pressure limits. You still need to drop 10% off the charge and work it back up.

Examples of the effect of dfferent cases based on theoretical calculations in QuickLoad to match peak pressure:

Hornady 55 grain FMJ BT
AA 2230
COL 2.20"
45,600 PSI peak pressure

Federal .223 case weighing 95.4 grains:
25.00 grains AA 2230
20" MV: 2,967 FPS

WCC 77 case, weighing 88.3 grains:
25.57 grains 2230
20" MV: 2999 FPS

WCC 92 case, weighing 93.2 grains:
25.14 grains AA 2230
20" MV: 2,972 FPS

Other calculations: To match peak pressures in the Federal case to the WCC 77 case requires about 25.6 grains of AA 2230 be used in the WCC 77 case. Matching velocity requires between 25.3 and 25.4 grains be used in the WCC 77 case. Matching barrel times (needed to keep a load located in a barrel vibration sweet spot) requires 25.5 grains of AA 2520 in the WCC 77 case.
__________________
Nick
__________________________
Orange Hat Family Member
CMP Certified GSM Master Instructor
NRA Certified Instructor
NRA Patron Member
"First contemplation of the problems of Interior Ballistics gives the impression that they should yield rather easily to relatively simple methods of analysis. Further study shows the subject to be of almost unbelievable complexity." Homer Powley

Last edited by unclenick; 04-30-2007 at 10:28 AM.
Reply With Quote
  #4  
Old 04-30-2007, 10:44 AM
Beartooth Regular
 
Join Date: Feb 2004
Location: LA
Posts: 109
Thanks Nick. This is what I'm afraid of. I know just enough about reloading to be dangerous. I know that you shouldn't load a .223 case for 5.56mm. I don't use a chronograph and I always have a mixed bag of brass for whatever caliber I'm loading. I'm not a dedicated benchrest shooter, I'm usually just looking for a middle of the road cartridge that will be safe in my firearms and be reasonably accurate for blasting cans. Surely this can be achieved without segregating and weighing individual brass cases and keeping meticulous records of which brand primers I'm using with which powder. I know that this can cause variations in pressure, but companies like Georgia Arms do reloads that function fine in a wide range of brass casings.

I always start at the low end of a load, but I've always been a little unsure of what is meant by "working up" the load. Does that merely mean increasing the powder load and then looking for signs of overpressure (e.g., sticking cases, flattened primers, stretch marks or shiny rings on the case)?

As a side note, my .223 reloads are shot in AR-15's that are chambered and designated for 5.56mm.
Reply With Quote
  #5  
Old 04-30-2007, 12:40 PM
unclenick's Avatar
Super Moderator
 
Join Date: Jan 2005
Location: Hilliard, Ohio
Posts: 10,798
Accuracy requirements are in the eye of the beholder, always. You may have noticed that JR454's loads all predicted a safe pressure with all the cases. It will probably turn out to be fine with all your cases, but you need to test that hypothesis. Also notice that not even within one brand (WCC) is the lot-to-lot weight a good match.

The dangers of mixing NATO 5.56 mm and commercial .223 are really just about two things: The softer commercial brass cannot be trusted to extract reliably in full-auto (the rims can break off) and the NATO chambers have long throats to accept a wide range of military bullet nose profiles without any of them jamming into the rifling. Some NATO loads are not safe in some commercial chambers because of that jamming. In .308, the maximum NATO chamber is enough longer than the commercial minimum, there is danger of creating premature case failures in the form of head separations. Frank White, at Compass Lake Engineering (AR match rifle builder) tells me that difference does not exist between chamber specs for the 5.56 mm NATO and .223 Rem, but I think that is for Match chambers only. Clymer makes the NATO standard reamer headspace 0.004" longer, while the throat freebore grows from 0.025" in their .223 Rem reamer to 0.050" in the NATO. The worst likely consequence is shortened brass life in the longer chamber. You can fix that by sizing your cases only enough so they come out with the headspace 0.002" shorter than as fireformed, whatever that is in your chamber? That will get your case life back, for the most part.

There is also misinformation in the Wikipedia and other places about chamber pressure limits. The military limit is actually 10% lower, for ball, than the commercial limit. However, commercial ammo makers are timid about law suits and often underload appreciably, while the military tries to hit its numbers. As a result, a lot of surplus military ammo is hotter than its commercial counterparts, despite the lower maximum pressure specification.

You'll be interested to know that in any gun that fires at over about 30,000 PSI (most modern rifles), the brass sticks to the chamber wall while the casehead, having at first been pushed forward against the headspace determinate by the firing pin, stretches the brass near the internal corner of the casehead and case web (wall) to get all the way back against the bolt face. The case thus grows inside during firing (fireforming). Peak pressure will depend on this enlarged volume, not on the volume the case started with. The enlarged volume is sized by your particular chamber, and is why loads safe in one gun are sometimes unsafe in another of the same nominal chambering. All but light loads need to be worked up for your particular gun.

You are correct about working up and watching for pressure signs. Normally one works loads up in .3 grains increments. Assuming your scale is accurate +/- 0.1 grains and has 0.1 grains of resolution, .3 grains is the smallest increase you can make and be sure two consecutive charges are actually different. In 0.2 grains increments, you might throw one charge at +0.1 grains and the next larger charge at -0.1 grains, and actually end up with the same charge in both cases. So, start about 2.4 grains low, and work up in 0.3 grain increments, one round at a time, watching for pressure signs, as you suggest. I will add that you want to use cases that are selected to be examples of the heaviest ones you load. These will have the least powder space and produce the highest pressures.

A chronometer is useful because it offers one additional pressure sign. In most rifles, as you get near maximum pressure, adding more powder stops increasing the muzzle velocity. In general, you will have exceeded your most accurate load by the time you reach this point and groups will be opening up. Most of us are not interested in loads hot enough to reduce accuracy.
__________________
Nick
__________________________
Orange Hat Family Member
CMP Certified GSM Master Instructor
NRA Certified Instructor
NRA Patron Member
"First contemplation of the problems of Interior Ballistics gives the impression that they should yield rather easily to relatively simple methods of analysis. Further study shows the subject to be of almost unbelievable complexity." Homer Powley

Last edited by unclenick; 04-30-2007 at 12:59 PM. Reason: Corrections
Reply With Quote
  #6  
Old 04-30-2007, 06:34 PM
Beartooth Regular
 
Join Date: Jul 2005
Location: Jacksboro, TX
Posts: 179
Nick,
That Quick load is quite the program. It just so happens that the velocity I'm getting with the 25g of AA2230 is averaging 2920fps. This is with mixed commercial brass (Rem. and Win. and Fed.)
And as you mentioned about increasing the charge, the mv I get when 25.5g is used averages only 2870 fps.
This is from my Rock Rivers AR15 (or, CAR 15 as they call it), with a 16" barrel.
It too is chambered for the nato cartrige. I havent played too much with seating depth with this, just seating to the crimp groove on the bullet. The magazine wont allow much deeper seating....but I'm getting off the subject..

JR
Reply With Quote
  #7  
Old 05-01-2007, 11:31 AM
Beartooth Regular
 
Join Date: Feb 2004
Location: LA
Posts: 109
Thanks guys. That was valuable info. I think I'll get a chrono. They don't seem to be very expensive and I'll get a bit more data to help me reload safely.
Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Military Duplicate Load Using Unique Powder 123ODC Handloading Procedures/Practices 1 03-19-2007 10:31 AM
Bad Accident With Handloads at the Gunrange Today kdub Handloading Procedures/Practices 53 08-13-2006 09:09 AM


All times are GMT -8. The time now is 11:14 AM.

< Contact Us - Shooters Forum - Archive >

 
 

All Content & Design Copyright © 1999-2002 Beartooth Bullets, All Rights Reserved
View Privacy Policy | Contact Webmaster | Legal Information
Website Design & Development By Exbabylon Internet Solutions
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.0 PL2