.308 rounds wont fully load.

[NeTo]

Hey guys I can't seem to find it answers with the search. I have a AR10 that i have been reloading rounds for they won't fully load in the action the bolt stops about 3/4 of the way then it's a pain to try and eject the unspent round. They are full length sized and twice fired brass. I can usually get one out of every 5 or 6 to fully load and fire off but that's not good odds at all, am I doing something wrong. Any help would be great thank you for your time.

The gun is a Palmetto state arms upper and lower

 

[spife7980]

Does the empty brass chamber post sized without a bullet? What's your fired vs sized shoulder measurements?

Does factory chamber?

 

[NeTo]

The brass does chamber after it is sized.The size after fire is .457 and after size and load is .456 some of the factory ammo I have measured around .454 that seems a little tight but I'm still a little new

 

[zeroz]

One of my buddy's ar 10's required a small base die to chamber. He had all sort of chambering and extraction problems. Small base solved them all. Might give that a shot.

 

[BRU15]

Sounds like you need a small base!

 

[JMGlasgow]

As others have stated, you might need a small base sizer die. I had the same issues in my M1 Garand. It even ripped rims off the case and stuck brass after firing, assuming it chambered.

Some semi autos need a small base die, others don't. My M1A SM doesn't need small base, and as said earlier, my Criterion barreled Garand does.

 

[FLIGHT762]

You are likely not bumping the shoulders back enough on your fired brass. How are you measuring your shoulder bump? If you're not using some type of gauge, you are just guessing on your F/L resizing. Take your F/L die and unlock the locking ring and turn the die into your press another 1/8th of a turn. This might be your problem. You don't know unless you use a gauge which shows where you're at with your F/L sizing. Different makes of brass will resize at different rates depending on the spring back on the cases and how many times they have been fired and have been work hardened.

You can get away with turning your F/L die in until you get cases that will chamber 100%. Turning your die in sometimes it is just turning it in a 1/16th of a turn or less. Once you get close to where you need to be, it is a very small / fine adjustment. It's not likely you need a S/B die. The only rifle I needed a S/B die was a Steyr SSG 69 that had such a tight chamber, the cases weren't being sized enough at the case web. Any cases that were over .4685" at the case web would not chamber. A Redding S/B body die took care of this. A RCBS small base die wouldn't do it.

Are you crimping your bullets? Over crimping can cause the case shoulder to buckle slightly and will cause cases not to chamber. If you're crimping, back off the crimping die.

 

[GhengisAhn175]

It can be two issues, your chamber could be tight ,
hence the need for a small base die

or

youre not bumping your shoulders back enough. I think it's the shoulders.. reason being you quoted ".457, .456, .454" when someone asked you about shoulder bump. Don't know HOW you're getting those #'s.

You need to get the measurement for your shoulder datum line

 

[scudzuki]

The dimensions he posted look like diameters at the shoulder to me, not lengths.

 

[mrjinglesusa]

The dimensions he posted look like diameters at the shoulder to me, not lengths.

Yep. The measurement to shoulder datum line on .308 should be 1.6XX. SAAMI: 1.630 GO, 1.634 NO GO, 1.638 FIELD

 

[MtnCreek]

Are you crimping your bullets? Over crimping can cause the case shoulder to buckle slightly and will cause cases not to chamber. If you're crimping, back off the crimping die.

I believe this is the problem.

 

[NeTo]

I am crimping the rounds. I will take a look at the measurements again when i get off work, and give a few suggestions a try. Thank you for all the help i will post an update with a few pics as well.

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[Xinarin13]

One of my buddy's ar 10's required a small base die to chamber. He had all sort of chambering and extraction problems. Small base solved them all. Might give that a shot.

That's what I have

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[wxl]

Agree you need to check shoulder bumping. Sounds like you do not understand comments about bumping the shoulder back. Instructions from die manufacturers do not tell you how to do this. The recommended amount to screw in die assumes it is enough to bump shoulder back for average rifle. Screw die down a bit as suggested above until brass will chamber.

 

[digrazir]

I always use small base dies when reliable reloading for a 308 gas gun..function first and accuracy second..Ray

 

[Darkside-Six]

Sounds like you need a small base!

This. Try a small base die. I've had the same thing happen and it corrected it.


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[wxl]

Load for AR10 and M1A and standard dies have performed satisfactory. Do have a small base but rarely needed to resize brass (even purchased 1X LC that may or may not have been machine gun fired).

 

[digrazir]

Load for AR10 and M1A and standard dies have performed satisfactory. Do have a small base but rarely needed to resize brass (even purchased 1X LC that may or may not have been machine gun fired).

Using standard dies will never get your fired brass back to unfired diemensions. A small base die will. This especially comes into play using once fired military brass. In many cases, such as yours it doesn't appear to make a difference. Even though the brass might be a little tight in the chamber the gas system may be overcompensating and just extracting and ejecting with pure brute force. That said using small base dies in a sem-automatic hurts nothing. Ray

 

[wxl]

Originally posted by wxl View Post

Load for AR10 and M1A and standard dies have performed satisfactory. Do have a small base but rarely needed to resize brass (even purchased 1X LC that may or may not have been machine gun fired).

Using standard dies will never get your fired brass back to unfired diemensions. A small base die will. This especially comes into play using once fired military brass. In many cases, such as yours it doesn't appear to make a difference. Even though the brass might be a little tight in the chamber the gas system may be overcompensating and just extracting and ejecting with pure brute force. That said using small base dies in a sem-automatic hurts nothing. Ray

True I may be lucky but I measure my shoulder set back and loaded rounds drop in my Wilson case gauge (added check) easily. Do not have issues with hard to chamber or extraction/ejection

 

[FLIGHT762]

True I may be lucky but I measure my shoulder set back and loaded rounds drop in my Wilson case gauge (added check) easily. Do not have issues with hard to chamber or extraction/ejection

Just be aware the drop in Wilson type gauges only measures shoulder bump and case length. They DO NOT measure case head dimensions. The Sheridan gauges and the JP Enterprise gauges are cut with a chamber reamer and do measure other dimensions. Cases and loaded ammunition that pass these gauges will chamber in SAAMI chambers.

Also, the down side with all of the drop in gauges is they can and do give a false reading if the case rim is bent or has a small burr on it. The case will drop in and show what appears to be excessive shoulder length when in fact it is just a burr or slightly bent rim that will chamber.

 

[NeTo]

So i broke down and purchased a small base die that did the trick the rounds load without failure. Thank you guys for your comments and suggestions i will try and post a few before and after pics when i get home not sure how to do that yet with this app.

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[NeTo]

This is before the small base dies

This is after using the small base dies

A few finished rounds

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[digrazir]

The resistance to using small base dies when reloading for a semi- auto never ceases to amaze me...I always use them...because they work..Ray

 

[ramboskie]

Get one of the BJ's case gauge, if the brass will go in it then you should be good to go