7SAUM virgin brass to 1x fired.

[Mxracer532]

So I loaded some 180 ELDM'S yesterday and loaded all the way up to 61.4g of RL23 till I got notable ejector marks. No sticky bolt.
Today with same 180 ELDM'S with 1x fired brass and 60g of RL23 I had a very sticky bolt and just quit.
Is it normal to have to drop powder charge that much from virgin to fire formed? If so how much cause I still have to drop and don't know how much. Thanks

 

[TheOfficeT-Rex]

No carbon ring?

How many of each load did you fire for each string?

 

[Mxracer532]

No carbon ring?

How many of each load did you fire for each string?

I shot 3 of each.
I am unsure on the carbon ring. It has about 40 rounds down it since it's last cleaning. Only 50ish rounds down the barrel total.

 

[Steel head]

It’s common for once fired brass to require less powder to get a certain speed than virgin brass.
How much depends on your headspace and chamber.
On my 7 saum brass grows less than .002 on firing and a .3-.4 grain difference to achieve same speed.

 

[Mxracer532]

It’s common for once fired brass to require less powder to get a certain speed than virgin brass.
How much depends on your headspace and chamber.
On my 7 saum brass grows less than .002 on firing and a .3-.4 grain difference to achieve same speed.

I understand that, what's got me stumped is going down 1.4g from what I was shooting before without a sticky bolt to having a very sticky bolt with 1.4g less powder.
I shot 60.4g of virgin brass with 180's just after I had the sticky bolt at 60.0g on 1x fired brass with no issues.

 

[Steel head]

It’s simple.
1-possibly your chamber lets your brass expand more than mine.
2-your initial load was just on edge (If not beyond) and you have to compensate more.
3-on a new barrel a good practice is to once fire your brass with a mild load, you get it up to speed and avoid the pressure problems you’ve already experienced.

60ish grains is right there with my loads for 180’s with R23 and R26 and it’s not mild but safe in my barrels.
61 something is way up there.

 

[Mxracer532]

It’s simple.
1-possibly your chamber lets your brass expand more than mine.
2-your initial load was just on edge (If not beyond) and you have to compensate more.
3-on a new barrel a good practice is to once fire your brass with a mild load, you get it up to speed and avoid the pressure problems you’ve already experienced.

60ish grains is right there with my loads for 180’s with R23 and R26 and it’s not mild but safe in my barrels.
61 something is way up there.

I guess I will drop down to 59.4 ish and see what happens. I don't have anymore time to really dial a load to the nats ass. Moose tag starts Oct 1st and I won't be in town all this weekend and leave for moose camp the following. So I gotta make something happen this week after work.

 

[Steel head]

59.5-59.8 is generally a nice sweet spot in my barrel with ADG brass and 180-190 bullets.

 

[Mxracer532]

59.5-59.8 is generally a nice sweet spot in my barrel with ADG brass and 180-190 bullets.

Sounds good. Thanks man.
I did have a pretty good group with 180VLD's.
I also shot some 162 ELDM's I had from my old 7mm that hammered with H4350. .265 4shot group.

 

[PhilCo]

Two theories about loading new versus fired brass.
1. New case capacity is less since it has not been enlarged by fireforming. Loading this case a second time will require more powder since it is now greater in capacity.
2. (This has been my experience). When new brass is fired some of the internal pressure that would be used for bullet velocity is used to fireform the case. If the same powder charge is used a second time the bullet velocity will be greater since the case has already been fireformed; more pressure available for velocity. To get the same velocity in the second firing I have needed about a one grain reduction in powder for the 6.5 PRC and 7 SAUM.