Reloading for semi autos

FoxAlpha

FoxAlpha

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Here’s a bit of a two part question for all you hand loading veterans

First:
When you guys are loading for a semi-auto, do you always run your load development rounds through the magazine or do you single feed each round?

Second:
Can one expect any noticeable change in accuracy when feeding from a magazine vs single fed?


Here’s my background predicament and reason for asking. I have 3 batches of load development I want to run through my stag10 in 308 but cannot seem to find a happy medium in terms of reliability in feeding the gun. I’ll tune the adjustable gas block for whatever cheap ammo I used to sight in the rifle (AE762 & Hirtenberger) but when I tried running FGMM 175gr & 168gr it would not feed reliably. My idea was to get the rifle sighted in with cheap stuff and confirm reliable function, then switch to the factory match ammo to confirm, then start testing my handloads. Now I can’t find anymore FGMM locally to spend a more in-depth look at tuning the rifle to work reliably so I’m wondering if I should just single feed my 3 batches of load developments or would that give me false positives as it wouldn’t be run from a magazine?

Again, I have no idea what the answer is here so any direction or insight is appreciated.
 
Tune it with your load. Your turning it down to function on plain white rice. Add some pepper, if your lucky it likes hot peppers.

Our powder guru, Ganderite, gave some advice on powder for semis. Run a faster powder for the caliber in semi's. The peak of the presure has passed before activating the action. So full power, yet easy on the rifle.
 
The highest chance of a slam fire is when a single cartridge is loaded and not fed from the magazine to slow bolt velocity and firing pin inertia.

Meaning if you drop a cartridge in the chamber and let the bolt slam home there is a chance it might go bang.

The firing pins on the M14 and M16 rifles had their firing pins lightened to help prevent slam fires.

It is also recommended to use primers with a cup thickness of .025 to help prevent slamfires.

CHOOSING THE RIGHT PRIMER - A PRIMER ON PRIMERS
http://www.sksboards.com/smf/index.php?topic=56422.0

CCI 400 -thin .020" cup, not recommended for AR15 use by CCI/Speer. Good for .22 Hornet, .30 Carbine. See Note 1 at the bottom of the page.

NOTE 1: According to Speer/CCI Technical Services - Both the CCI 550 Small Pistol Magnum and CCI 400 Small Rifle primers are identical in size. Both primers use the same cup metal and share the same cup thickness. Both primers use the same primer compound formula and same amount of primer compound. They can be used interchangeably.
 
I test all my hand load from the magazine. If it does not function it is useless.
Full lengh resize you brass. Adjust for .004 to .006 of headspace. i use a small base sizer in all my semi's.
Start with an OAL of 2.800 - 40-42 gr of Varget and a 168 grains bullet. Make sure you have .002-.003 of neck tension. No need to crimp.
This should work. Use CCi primer. One trick is to uniform primer pocket...this make sure all primer are seated low.

Adjust you gas block for standard .308 factory load - and leave it alone.

You should fire a few box of match ammo in your gun to establish a base line. You want your reload to shoot equal or better than match ammo. In this regard, Federal Match is first rate. More reference you have, better your data will be. This will give you a very good idea what to expect from your system.

Make sure you gun work 100% with factory ammo first - that it feed from the magazine without jams or malfunctions.if not, find the problem and fix it.it is useless to try to develop a load for un gun that don’t work.
 
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Janeau said:
I test all my hand load from the magazine. If it does not function it is useless.
Full lengh resize you brass. Adjust for .004 to .006 of headspace. i use a small base sizer in all my semi's.
Start with an OAL of 2.800 - 40-42 gr of Varget and a 168 grains bullet. Make sure you have .002-.003 of neck tension. No need to crimp.
This should work. Use CCi primer. One trick is to uniform primer pocket...this make sure all primer are seated low.

Adjust you gas block for standard .308 factory load - and leave it alone.

You should fire a few box of match ammo in your gun to establish a base line. You want your reload to shoot equal or better than match ammo. In this regard, Federal Match is first rate. More reference you have, better your data will be. This will give you a very good idea what to expect from your system.

Make sure you gun work 100% with factory ammo first - that it feed from the magazine without jams or malfunctions.if not, find the problem and fix it.it is useless to try to develop a load for un gun that don’t work.
Click to expand...

Thank you, this was the consideration I was hoping to see.
I agree whole heartedly, it seems foolish to test a load that won’t run the gun as it’s intended to be ran but I wanted to confer with the minds here in case I was overlooking something.

I suppose I’ll have to shelve my load testing on my stag10 until I can find some more factory ammo that is comparable to the 175gr FGMM and get it running reliably again.
 
Why is my Winchester Model 100 so inaccurate? Just kidding, I know it's a piece of junk.

But to add to the conversation, I use CCI 400 in my AR15 without any issues. I've used up about 500 of them with no slamfires. When I eject an unfired case, I don't notice any dent on the primer. I think it becomes more of an issue with a dirty firearm where the firing pin gets stuck forward.
 
Guys I’m just going to clarify something here as it seems the topic of this really shifted to slam fires and load details for some unknown reason.

I’ve no concern of slam fires or any of that, I’m just simply interested in knowing how many of you single feed or mag feed when reloading for a semi auto, and if anyone has ever noticed any accuracy degradation when single feeding or magazine feeding.
 
with Semi's you have to

1 Slow the bolt down by Loading from the mag or riding the bolt handle app 3/4 of the way then letting it go Home .... Safer to just load from the mag

2 you can not have the bullet out too far ... IE .. touching the rifling

3 Use the correct Powder Range for rifle

4 Use the correct or Harder Primer .... reduces the chance of slam fire

5 Use the correct bullet weight .. approved / recommended for your rifle / barrel twist

your results may be different .... but this is what I do
 
FoxAlpha said:
Guys I’m just going to clarify something here as it seems the topic of this really shifted to slam fires and load details for some unknown reason.

I’ve no concern of slam fires or any of that, I’m just simply interested in knowing how many of you single feed or mag feed when reloading for a semi auto, and if anyone has ever noticed any accuracy degradation when single feeding or magazine feeding.
Click to expand...

Nope, not even with soft nosed bullets like the 65gr Sierra Gameking in a 5.56 AR15 that really hits bullets hard into the feed ramp. My Model 100 on the other hand angles the rounds up in the magazine so the bullet nose almost has a free ride into the chamber. Still inaccurate as heck ;-). Whether with H4895 or otherwise. Dumb design with the front stock screw being in the gas block. But I digress...
 
FoxAlpha said:
Thank you, this was the consideration I was hoping to see.
I agree whole heartedly, it seems foolish to test a load that won’t run the gun as it’s intended to be ran but I wanted to confer with the minds here in case I was overlooking something.

I suppose I’ll have to shelve my load testing on my stag10 until I can find some more factory ammo that is comparable to the 175gr FGMM and get it running reliably again.
Click to expand...


The Federal Match 168 grains is very accurate load and work great in AR. You can use it to tune your gun. It should work like clockwork with that. You should not have to adjust your gas block for your reload when you will use the 175, when you get that powder charge right. No need to go to max, use what make you gun shoot well and function all the time.
Use Varget to start until proven not giving good result in your gun. There is other good powder for the .308, but Varget is a know performer with the 168-175 match load.

Keep that AR well lubed and have fun !!
 
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