Loading 223 for an SCI-20

[mpmo]

Just getting started with .223 loading.   Have pretty decent experience with 9 and .45.  Anything specific to recommend for loading for an SCI-20 w/Cmore C3?  Nothing in my neck of the woods is past 300yds.  Planning on starting with new Starline brass, CCI 400, CFE 223, Berry's 55gr, Hornady standard dies, Hornady LNL.

 

Thanks!
 

 

 

[George16]

 Make sure you lube the cases really well during the decapping and resizing stage. Hornady One Shot or any lanolin-based lube will work.

 

I made my own lien using one part pure lanolin to 12 parts 99% alcohol (HEET in the red bottle). You can buy the pure lanolin from any drugstore or Amazon and HEET from any auto parts store.

 

 

 

 

[mpmo]

Got my SCI-20.  REad the manual.  It made reference to a loading doc on their website!  Pretty cool!

 

https://jprifles.com/document_pdfs/JP Loading Document_757.pdf

 

 

[HesedTech]

2 hours ago, mpmo said:

Got my SCI-20.  REad the manual.  It made reference to a loading doc on their website!  Pretty cool!

 

https://jprifles.com/document_pdfs/JP Loading Document_757.pdf

 

 

This is a great article and your new rifle looks like it will be a lot of fun.

These things from the article are essential:

"

1. The finished round must be a drop fit to the chamber to ensure that the bolt will reliably close over the cartridge.

2. You must load to an overall length (OAL) that will never interfere with the magazine’s interior dimensions.

3. The round must provide a pressure curve upon ignition that will reliably cycle the action without dropping a primer or causing excessive case head flow into the ejector cut.

"

#1 is the least intuitive for reloading 223 and a must is to use a good chamber gauge for checking the loads. The JP Enterprise is probably the best.

https://jprifles.com/buy.php?item=JPCG-223

 

I have to also add when reloading used brass one of the issues is often the groove in the case rim is slightly damaged during ejection and will not allow the brass to gauge check. 

 

For close in tactical shooting, almost any powder in the range CF223 will work and these days I'm using whatever brand of SRP I can get, they all work so far. 

Stick powders don't measure as well from the typical drop powder measure.

 

Inside of 200 yards almost any cheap FMJ 55 grain bullet will be accurate enough. Beyond that a heavier bullet, 65 - 75 grains, will give more reliable hits. Rifle twist these days is typically 1:7 or 1:8 both will work fine with the heavier bullets.

 

I have regular and small base dies for 223 from Lee, RCBS and Redding. They all work just fine, but unlike pistol it is a must to use your gauge checker (or barrel) to test the sizing die on your press. It normally requires going over center (all Dillons will do so) on the press to get the shoulder bumped to the correct length. If the press won't over center then get the shell holder in a different size/thickness to set the shoulder. Both RCBS and Redding sell these.

 

OAL as far as chamber goes is not an issue in AR platforms. The max length is 2.26 because that is the standard size for the magazine. I load for ARs at 2.245.

 

Yes loading good reliable rifle rounds is a bit more work than the typical pistol caliber, but it sure makes a difference when every one goes bang in the middle of a timed competition.

 

Enjoy. It's a great journey!

 

 

 

 

Edited December 8, 2021 by HesedTech

[mpmo]

I've heard from several people that the ideal bullet jump is 0.020".  I have measured my OAL with the Hornady gauge and the max is 2.320.  So that would make my ideal OAL around 2.300.  However as @HesedTech says above, the magazines I'm using won't feed anything longer than 2.26.  I have tested this in the gen 3 P-mags.  I'm even cautious to load that long as it seemed like it was about the ragged edge of reliability.  But am I sacrificing accuracy in making the bullet jump 0.050 farther than ideal?  Can I do anything about this?  Are there different mags I should be looking at?

 

 

[AHI]

You are trying to use bolt gun loading techniques to load for a semiautos.

from JP

, the functional aspect of the ammunition in a semi‐automatic platform precludes  some of the accuracy tricks that you might be accustomed to employing on your bolt gun ammo. 

 

 

load to just under magazine length. Try different bullets. I will give an example . Hornady 55 fmj will

"jump" more than a Hornady 55sp. A sierra 77 bthp match jumps even less. In most chambers .if you want to single load

there are bullets for that also.

Edited February 1, 2022 by AHI