Sizing the web

[Max_The_Phoenix]

Hi
Last night I was trying to resize my 2 times fired 308 winchester brass for my AR10
I bumped the shoulder 0.003 and tried sliding the brass in the chamber and saw it will stop very close by the web area and it doesn’t fully chamber.

I don’t have cam over but If I do cam over it will push the shoulders about .010 which is a lot.

I didn’t have any problem so for with my 6.5 cm bolt action so far after resizing the brass.

-What is the best solution to fully size the body without pushing the shoulders back to much?
- I don’t wanna try shaving my die or shell holder just looking for a good and clean solution.

- is this going to happen to the brass for my bolt action even the brass is fire forming in the chamber?

 

[KnowNothing256]

One of the simplest ways to adjust shoulder bump is the RCBS Competition Shellholder sets, this is my preferred method. The cheapest way to adjust it is to slip a feeler gauge between the top of the shellholder and the bottom of the die, but I don't recommend it, it's a pain. The most expensive way to do it is to get a sizing die that can change shoulder bump; there are micrometer-type dies, or the SAC die uses shims inside the die.

If you're floating the sizing die (sounds like you are), there's a good chance you're getting inconsistent sizing that could lead to chambering problems. I wouldn't think your web diameter is too large, but I could be wrong. What method are you using to measure this 0.003" shoulder bump?

 

[Max_The_Phoenix]

One of the simplest ways to adjust shoulder bump is the RCBS Competition Shellholder sets, this is my preferred method. The cheapest way to adjust it is to slip a feeler gauge between the top of the shellholder and the bottom of the die, but I don't recommend it, it's a pain. The most expensive way to do it is to get a sizing die that can change shoulder bump; there are micrometer-type dies, or the SAC die uses shims inside the die.

If you're floating the sizing die (sounds like you are), there's a good chance you're getting inconsistent sizing that could lead to chambering problems. I wouldn't think your web diameter is too large, but I could be wrong. What method are you using to measure this 0.003" shoulder bump?

I am using the hornady full length bushing die and hornady shell holder, press is the Forster Co-Ax
and then measure the shoulder bump with SAC gauges

My issue is not shoulder bump, its the web that doesn’t get sized in the die

 

[KnowNothing256]

I am using the hornady full length bushing die and hornady shell holder, press is the Forster Co-Ax
and then measure the shoulder bump with SAC gauges

My issue is not shoulder bump, its the web that doesn’t get sized in the die

Well, I would suggest that all you really know is that some part of the case isn't fitting in the chamber. But you don't know that it's the web; the web is just the last part to enter the chamber, so if you have a restriction anywhere, even at the neck let's say, you'd see the web sticking out.

It's theoretically possible to measure the web diameter at a certain datum (typically 0.200" from the case head), but it's not super easy to measure at exactly that datum without a fixture. I dunno, I'm not a machinist, maybe it's easier than I think.

 

[Haney]

Hi
Last night I was trying to resize my 2 times fired 308 winchester brass for my AR10
I bumped the shoulder 0.003 and tried sliding the brass in the chamber and saw it will stop very close by the web area and it doesn’t fully chamber.

I don’t have cam over but If I do cam over it will push the shoulders about .010 which is a lot.

I didn’t have any problem so for with my 6.5 cm bolt action so far after resizing the brass.

-What is the best solution to fully size the body without pushing the shoulders back to much?
- I don’t wanna try shaving my die or shell holder just looking for a good and clean solution.

- is this going to happen to the brass for my bolt action even the brass is fire forming in the chamber?

You can't finesse it to not bump it 0.007 from cam-over to no cam over ?

 

[Max_The_Phoenix]

You can't finesse it to not bump it 0.007 from cam-over to no cam over ?

No, like I said in cam over I have about 10 thou shoulder bump

 

[FLIGHT762]

Before going out and spending more money on a small base die, Try some more shoulder bump. Some Ar-10's are over gassed and you might be getting more shoulder stretching as the bolt is unlocking, giving you a longer shoulder than the chamber is.

M-14's are more notorious for this.

I have a buddy that has a les Baer AR-10. It fires Factory, Federal GMM and his fired cases shoulders stretch .010" over SAAMI minimum. No fucking way that chamber is cut .010" over SAMMI minimum. He gives me his once fired cases. I couldn't believe the case shoulders being blown forward that much, but measurements confirmed it.

My GAP 10 shoves case shoulders .004"- 005" from where I bump them. I size my case shoulders to about 1.630" (SAAMI minimum for 308 win). I have two 308 Gas guns, A GAP 10 and SR-25. I size the cases so they will chamber in either rifle. I've had no issue with case head separations. I've had about 10 loadings on some cases. Primer pockets go out before any other issues.

If you do need a small base die, I would recommend a Redding Small Base Body Die. They will size the case web down to about .4685". I only had one Rifle that actually needed it, it was a Steyr SSG 69 with a very tight chamber. I reload for several 308 Rifles.

 

[wade2big]

When you push the resized case in the chamber and it stops, will it pull right out or is it stuck to where you have to use a cleaning rod down the muzzle to pop it out of the chamber? If it’s the former, it is more than likely a shoulder bump issue. If it is the latter, then you probably need a small base die.

When you bumped the shoulder .010”, did it then chamber?

 

[Max_The_Phoenix]

Before going out and spending more money on a small base die, Try some more shoulder bump. Some Ar-10's are over gassed and you might be getting more shoulder stretching as the bolt is unlocking, giving you a longer shoulder than the chamber is.

M-14's are more notorious for this.

I have a buddy that has a les Baer AR-10. It fires Factory, Federal GMM and his fired cases shoulders stretch .010" over SAAMI minimum. No fucking way that chamber is cut .010" over SAMMI minimum. He gives me his once fired cases. I couldn't believe the case shoulders being blown forward that much, but measurements confirmed it.

My GAP 10 shoves case shoulders .004"- 005" from where I bump them. I size my case shoulders to about 1.630" (SAAMI minimum for 308 win). I have two 308 Gas guns, A GAP 10 and SR-25. I size the cases so they will chamber in either rifle. I've had no issue with case head separations. I've had about 10 loadings on some cases. Primer pockets go out before any other issues.

If you do need a small base die, I would recommend a Redding Small Base Body Die. They will size the case web down to about .4685". I only had one Rifle that actually needed it, it was a Steyr SSG 69 with a very tight chamber. I reload for several 308 Rifles.

Oh Thanks so much my friend
Yes I can take it out and what is weird after the first firing period I was able to chamber them easily with 2 thou bump but now the web is 2 thou or so bigger

Does this happen to the gas guns only? Assuming the case doesn’t fire formed like bolt actions?

 

[Max_The_Phoenix]

When you push the resized case in the chamber and it stops, will it pull right out or is it stuck to where you have to use a cleaning rod down the muzzle to pop it out of the chamber? If it’s the former, it is more than likely a shoulder bump issue. If it is the latter, then you probably need a small base die.

When you bumped the shoulder .010”, did it then chamber?

No I can take it out easily if I don’t force the bolt to close, otherwise I have to pull the bolt very hard in order to eject it

 

[spife7980]

Just share your actual dimensions already. Base, shoulder and neck diameters-fired and sized-and then your shoulder set back via datum.

 

[Max_The_Phoenix]

Update:

I found a few more pieces of twice fired brass in my trunk and measured the headspace
It shows 1.498
Virgin hornady brass is 1.485
This makes me wondering I might have excessive head space in my chamber
Cause the bolt closes easily at 1.490
But bumping the shoulder 9 thou is a lot

What do you guys think?

Daniel Defense DD5 v4

 

[mmlook]

best way = roll size
good way = small base body die

 

[Max_The_Phoenix]

best way = roll size
good way = small base body die

I am using small body die from rcbs
But still the same issue
My main concern now is the excessive shoulder growth

 

[mmlook]

i would double check your trim length

and your chamfers/neck mouth

all of these will cause your brass to not chamber or feel tight when you close the bolt

 

[Max_The_Phoenix]

i would double check your trim length

and your chamfers/neck mouth

all of these will cause your brass to not chamber or feel tight when you close the bolt

The trim length is 2.006
My question is why should growth is a lot to begin with

 

[mmlook]

not uncommon for virgin brass to be 0.005-0.010” undersized

i don’t shoot .308 or hornady brass,
but all my lapua virgin brass is at least 0.005” if not closer to 0.007” undersized

 

[Doom]

AR10 chambers tend to be slightly larger than bolt action chambers. They are also sensitive to powder selection. Slower powders cause the camber pressure to be higher when extraction takes place this also is a function of gas system length. Adding an adjustable gas block doesn't change the chamber pressure during extraction. This can cause some case body expansion issues depending on how high the pressure is. It also possible your chamber pressure was higher on those rounds.

I'm betting the base is blown out (in the +/-.200 dimension area. This is a common issue, especially if the brass is fired in a different gun. The best solution is a small base die. This will reduce the about of setback on the shoulder as opposed to trying to size the base with a standard FLS die.

I also recommend a case gauge to check your brass as having a round stuck in the chamber can happen. Remember that the AR's don't have a primary extraction.

 

[Max_The_Phoenix]

AR10 chambers tend to be slightly larger than bolt action chambers. They are also sensitive to powder selection. Slower powders cause the camber pressure to be higher when extraction takes place this also is a function of gas system length. Adding an adjustable gas block doesn't change the chamber pressure during extraction. This can cause some case body expansion issues depending on how high the pressure is. It also possible your chamber pressure was higher on those rounds.

I'm betting the base is blown out (in the +/-.200 dimension area. This is a common issue, especially if the brass is fired in a different gun. The best solution is a small base die. This will reduce the about of setback on the shoulder as opposed to trying to size the base with a standard FLS die.

I also recommend a case gauge to check your brass as having a round stuck in the chamber can happen. Remember that the AR's don't have a primary extraction.

Really appreciate you for sharing this
Yes I am using the small base die for this process
Today I tested 50 rds with hornady virgin brass
I got some shocking results lol
43.7 Varget
Hornady virgin brass
168gr ELDM