Does size REALLY make a difference

Lilswede1 · November 17, 2009, 12:55 AM

Resized, trimmed and prepped 560 rds. of .223.
Measured them with a Precision Mic Gage during finally inspection and sorted them into various groups based on shoulder length.
All brass is LC 73 to 06. Shoulder lengths varied from -.003 to .011" with the biggest average being in the -.005" or -.009" bracket (using Precison gage for figures).
Tried to maintain a repetitve pressure and equal stroke on the resize press.
Still had variances.
Then I measured some factory ammo.
Winchester Varmit Grenade measured .003" to shoulder
Lake City reman w/ 50 gr Vmax measured .010" to shoulder.
Remington with 50gr FMJ measured .007"
I will load up 3 groups with shoulder lengths .003" -- .006" --- .010" and try them at the range to see if there is a noticeable difference.
If someone has tried the same thing would sure like to here from them.
By the way, don't have time to fireform these rounds so trying to get most accurate load I can with what I have.
Really stormy here in NW Wash so may be awhile before I can get to range.

steve4102 · November 18, 2009, 01:58 AM

Are you FL sizing or Neck sizing?

Quote:

Tried to maintain a repetitve pressure and equal stroke on the resize press.

If you have your sizing die set up correctly and you run the brass all the way up into the sizing die with the press camming over just a bit you should not need to worry about "pressure" on the press handle. All the way down with the handle is all the way down.

The only time I get variances in "head to shoulder" measurements is when I mix brass that has been fired different amounts. Brass that has been fired many times can become "work Hardened" and develop a lot a "spring back". Mix this brass with brass that is still soft and the H to S measurement will vary.

Lilswede1 · November 18, 2009, 09:43 AM

Brass is all LC but years vary from "77" to "93".
Am using a FL RCBS resizing die and use a q-tip to apply lube to inside of neck.
Purchased brass in bulk as "once-fired" but can only take sellers word for that.
Brass looks very good on inspection and cleaned up nicely in the tumbler - it appears to be as advertised.
Don't think I have a problem loading and shooting these rds. just wondered if someone else had experienced the same situation and what their results are.
Being the anal fanatic I sometimes can be, I will sort by year when boxing and final inspecting reloads.

**Mal H** · November 18, 2009, 10:11 AM

Personally, I think you're worrying way too much about this. But that aside, what exactly are you measuring, that is, from where to where?

You state "Winchester Varmit Grenade measured .003" to shoulder". It's not clear what case dimension is .003" on one case, .010 on another, and .007 on another.

Lilswede1 · November 18, 2009, 05:36 PM

The measurements above were all made using the Precision Mic Guage measuring headspace.
Also measurements should have a "-" in front of them indicating amount of distance below the "0" mark on the guage. My error - forgetting the "-". I have corrected it.
I was surprised to find the differences in factory ammo.
Back to original question - will the difference in headspace affect accuracy?

Slamfire · November 18, 2009, 05:44 PM

Quote:

Back to original question - will the difference in headspace affect accuracy

In a shoulder fired rifle? I don't think so.

This is in the noise compared to sight alignment, trigger pull, follow through, stock weld.

In a bench rest rifle, could be.

November 17, 2009, 12:55 AM	#1
Lilswede1 Senior Member Join Date: September 8, 2008 Location: NW Wash State Posts: 216	Does size REALLY make a difference Resized, trimmed and prepped 560 rds. of .223. Measured them with a Precision Mic Gage during finally inspection and sorted them into various groups based on shoulder length. All brass is LC 73 to 06. Shoulder lengths varied from -.003 to .011" with the biggest average being in the -.005" or -.009" bracket (using Precison gage for figures). Tried to maintain a repetitve pressure and equal stroke on the resize press. Still had variances. Then I measured some factory ammo. Winchester Varmit Grenade measured .003" to shoulder Lake City reman w/ 50 gr Vmax measured .010" to shoulder. Remington with 50gr FMJ measured .007" I will load up 3 groups with shoulder lengths .003" -- .006" --- .010" and try them at the range to see if there is a noticeable difference. If someone has tried the same thing would sure like to here from them. By the way, don't have time to fireform these rounds so trying to get most accurate load I can with what I have. Really stormy here in NW Wash so may be awhile before I can get to range.

November 18, 2009, 09:43 AM	#3
Lilswede1 Senior Member Join Date: September 8, 2008 Location: NW Wash State Posts: 216	Brass looks good Brass is all LC but years vary from "77" to "93". Am using a FL RCBS resizing die and use a q-tip to apply lube to inside of neck. Purchased brass in bulk as "once-fired" but can only take sellers word for that. Brass looks very good on inspection and cleaned up nicely in the tumbler - it appears to be as advertised. Don't think I have a problem loading and shooting these rds. just wondered if someone else had experienced the same situation and what their results are. Being the anal fanatic I sometimes can be, I will sort by year when boxing and final inspecting reloads.

November 18, 2009, 05:36 PM	#5
Lilswede1 Senior Member Join Date: September 8, 2008 Location: NW Wash State Posts: 216	Precision Mic Guage The measurements above were all made using the Precision Mic Guage measuring headspace. Also measurements should have a "-" in front of them indicating amount of distance below the "0" mark on the guage. My error - forgetting the "-". I have corrected it. I was surprised to find the differences in factory ammo. Back to original question - will the difference in headspace affect accuracy?

November 18, 2009, 10:11 AM	#4
Mal H Staff Join Date: March 20, 1999 Location: Somewhere in the woods of Northern Virginia Posts: 16,955	Personally, I think you're worrying way too much about this. But that aside, what exactly are you measuring, that is, from where to where? You state "Winchester Varmit Grenade measured .003" to shoulder". It's not clear what case dimension is .003" on one case, .010 on another, and .007 on another.