Harder bolt close after sizing

[47WillysGuy]

	His	Mine	Saami
A	0.453	0.453	0.455
B	0.470	0.470	0.470
C	1.5685	1.615	1.634 -0.007

I compared OP numbers to the SAAMi drawing and my .308 numbers and His "C" which is a headspace number is almost 0.065 of an inch different from Sami and 0.046 of an inch from my readings. I used the Hornady "D" insert to get the 1.615" my headspace dimension.

Saami's dimension from case head to body/shoulder junction is 1.5598, OP's dimension of His "C" is 1.5685 which gives a difference of almost 0.009 of an inch difference.

As dellet says, "But we need that length number at the .400” diameter of the shoulder to know for sure."

The 1.5685" dimension is suspect to me... What tools/method are you using to get the 1.5685" number?

 

[JMayo]

Here is another couple of thoughts ...

Sholder angle of die not matching chamber.

Calipers not reading correctly.

Method in which measurements are being taken.

Lol you've got from A to Z being thrown at you. Good luck. Let us know when you find that needle in that haystack !

 

[243winxb]

How does the competition shell holder screw things up and make the harder bolt close?

Makes the measured head to datum length longer, less head clearance. Your using the .004" making the case longer and harder to chamber. The shoulder is being pushed back less.
This also mean the die is not going down the case body the full length. A cam over press (RCBS) may also set the shoulder back 1 or 2 thousandths more, when camming over.

Standard dies and shell holders will for the most part, set the shoulder back .005" This works well in many bottle neck rifle cartridges. No case head separations issues. Best to always check for excessive sizing.

 

[243winxb]

I really can't put my finger on it. But for example, if I used .006 competition shell holder last time, this time the same shell holder does not bump it back enough. I don't.. it just seems I can not get consistent.

Fired brass does not fully expand to the chamber till near maximum loads are fire about 3 times. When the 6 shell holder didn't allow brass to chamber, move to 4, if that is tight in chamber move to 2. If 2 is a crush fit when closing the bold, you have waster you money on the Comp Shell Holder Set.

Comparators are to compare fired to sized brass only.

 

[JMayo]

A measurement is a measurement no matter the way it got there.

 

[lawrence97]

How does the competition shell holder screw things up and make the harder bolt close?

What tool are you using to measure shoulder bump?
Depending on if you are using a whidden, Hornady or something else it might be measuring on a part of the shoulder datum that does not show bump as much as measuring on a different part of the shoulder. You mentioned bumping .0015 ~ .002. My guess is you will get smooth closure in the .003~.004 shoulder bump range.

I don’t think you are bumping your shoulder enough!

Use a standard shell holder and screw the die down until the brass is resized properly and the bolt will close smoothly.

Even better if you can remove the firing pin assembly/spring when testing for proper sizing. With the spring removed your bolt should fall/close on a properly sized case.

 

[expiper]

How does the competition shell holder screw things up and make the harder bolt close?

the comp. shell holders make the ctgs, longer than a regular shell holder does,,,you are causing the problem by using them !!!...Roger

 

[Martin52]

Have these 6 x fired cases been fired from new in the same chamber ?

Does the base of your FLS die touch the shellholder ?

 

[Coyotefurharvester]

Single stage press, Redding fls, standard Redding shell holder, set die to touch shell holder at top of ram stroke. Place a lubed previously SIZED brass in and one time full stroke with 5 second dwell. Wipe clean and chamber. This may result in case measurement with Max headspace. Use the spent primer method to measure, if you find more than 0.003 primer protruding after chambering. Option 1 back the die out 1/8 turn and size a fired case and chamber(if tight turn die back to touch shell holder). 2. Use the competition shell holder that adjusts the correct amount. Example .006 primer showing, use the 4 holder to NOT size as much by 0.004 leaving you 0.002 clearance. WITH THE DIE GUTTED.

 

[Chiquita]

I don’t load 308, so I’m a bit confused with the numbers and the drawing.

Your “C” measurement is being referred to as “base to Datum” in your first post. This is base to shoulder. Base to datum would be measured as drawn, close to the center of the shoulder at a spot that is .400” diameter and should be somewhere around 1.630”. Note the drawing below.
View attachment 1314419
How are you getting your measurement?
Are you using a different diameter tool than .400” to get your 1.57+ number?
Are you just measuring to the shoulder with calipers?

As I said I’m not familiar with the 308 cartridge but your numbers don’t make sense to me.

If you are not measuring to the actual datum, it would all make sense. The shoulder will move forward and lengthen, before the die contacts the shoulder and pushes it back. This would cause your problem and using the standard shell holder would likely correct it.

But we need that length number at the .400” diameter of the shoulder to know for sure.

Use the sinclair comparator.

 

[Chiquita]

Thank you all for your replies. I have learned alot.

I am using Sinclair comparator.

The brass has been fired in this chamber only. HOWA 1500 .308

It is a Satrline brass,

The base of the die touches the shell holder.

I did try to remove the ejector pin from the bolt to no avail. I can not get the pin to move. I have already bent 3 punches.

The issue was that I was not bumping back enough. I bumped back 3.5 to 4 thousandths and the bolt closes fine. I will try this next time and see if it works.

I am still lost on why not to use the competition shell holder.

 

[Chiquita]

is your barrel tight,

I have not clue. I don't know how to check.

ETA: Sorry I thought your chamber. Yes The barrel is tight. At least I don't feel any movement.

 

[Sandstorm]

People that are over bumping their brass use the Competion shell holders to give them
less bump....-.004 less ...006 less and I think the number .010 is for no Bump.
This is how I was explained the process...( Ie: I dont use them myself )

 

[lawrence97]

Thank you all for your replies. I have learned alot.

I am using Sinclair comparator.

The brass has been fired in this chamber only. HOWA 1500 .308

It is a Satrline brass,

The base of the die touches the shell holder.

I did try to remove the ejector pin from the bolt to no avail. I can not get the pin to move. I have already bent 3 punches.

The issue was that I was not bumping back enough. I bumped back 3.5 to 4 thousandths and the bolt closes fine. I will try this next time and see if it works.

I am still lost on why not to use the competition shell holder.

Why are you trying to remove the ejector? Why would you think your barrel is loose?

Your problem should be solved now that your Sinclair gauge is showing 3.5~4 thousandths. If your only problem was not sizing brass enough at the shoulder then you are good from this point forward. Not sure why you would want to use the competition shell holders….. the chamber and your brass already disagreed with you trying to use them. Just because the shell holders say “competition” doesn’t mean you should be using them and they obviously aren’t working out for you.

What matters is that your bolt now closes easily on resized brass and your next step should be to anneal after firing or be consistent in all you do with your brass after firing.

Just because common theme on the internet is to only bump the shoulder .001 to .002 does not mean that is correct for your brass or chamber and we all have different tools to measure. Your brass will not suffer from over working by sizing to .004 or even .005. Different tools measure on different spots on the shoulder datum.

In the end I’d rather have smooth bolt closure over dealing with inconsistent cases that sometimes prevent the bolt from closing smoothly which introduces other issues if you start forcing the bolt to close.

 

[dellet]

Basically you have a chamber that is on the tight side.

If you look at the SAAMI drawing I posted, the length listed for maximum headspace length is 1.634” - .007”. Much of the time that number will be -.010”. So the competition shell holders have a range of minimum base to shoulder datum, to maximum .010”.

The standard shell holder is “0”. Minimum chamber, maximum bump.
The .010” shell holder is Maximum chamber, minimum bump.

It seems for some reason your insert is contacting the shoulder at a different place than where the chamber does. I know then Sinclair inserts are supposed to match the shoulder angle to contact the whole shoulder instead of just a single contact like the Hornady.

The question would be, what is the measurement now that you have a case that fits?
How does that compare to your other numbers you posted

 

[Ccrider]

I would have won my bet. One thing mentioned above you should consider. If your doe does not fit your chamber close, the die may be changing the angle of your shoulder, which clmay make you have to bump more than if you were using a custom die. No big deal, just bump them enough to get clearance and move on. .002 is not the magic number for all chambers. .004 works fine of that is what it takes. Truth is, if you are not getting clearance to you go .004, by your measuring, then you may be bumping .002 at some point, just depends on where on the shoulder you are measuring from.

 

[natdscott]

I am sure the SBD may help, but, why does a full sized case have harder time. It is smaller than a unsized case so that is what I don't understand.

That is an incorrect assumption. Abandon that, in favor of actually MEASURING what’s going on.

The brass gets squished all over the place in the die, so if one dimension of the die is too large, or SET too large, then the switching from other areas will usually fill that space. The result is a casing that was sized smaller in some dimension(s), but actually got larger in other(s).

 

[Kracken McGraw]

People that are over bumping their brass use the Competion shell holders to give them
less bump....-.004 less ...006 less and I think the number .010 is for no Bump.
This is how I was explained the process...( Ie: I dont use them myself )

This is correct .010 for least bump down to .002 for more bump. The standard shell holder will give the most bump back.

 

[JMayo]

I put a pma tool on my dies so i could make adjustments on the fly. To put the case in the action, if it scrubs move the pma a notch letting the die down .005 or less and keep doing that until no scrub.
@MrBarrel

 

[PracticalTactical]

My guess is the die is fat in the body and the chamber is tight in the body.

When the shoulder is pushed back during sizing, I'll bet its squatting the base of the case outward. Then its binding on the diameter, not the headspace.

I would try using a micrometer to monitor the diameter of cases near the base and track if that diameter is growing during sizing.

If this is in fact the problem, then consider using a small base die to ensure the body of the case is controlled.