First shot of load work ups always slower by 20fps - Page 3

**Unclenick** · January 15, 2014, 08:28 AM

I'll be interested to hear how the single loading goes.

Another thing you could set up to try is backing the load down maybe 5% and working up to same velocity with a magnum primer. Magnum primers can sometimes swamp out ignition variation by brute force where the powder isn't snug in the case.

Metal god · February 2, 2014, 11:52 AM

Went to the range yesterday . What I did was single shot loading and pulled the rifle in pretty tight to my shoulder . I also took the whole box of reloads and shook it up and turn it upside down to loosen up the powder in the case before loading the rifle . I should add that these test were of new loads of the same components and I shot the groups in a round robin way . I shot one shot of each load at a time letting the barrel cool completely between each shot .. My good load is/was 40.3gr of IMR 4064 . I wanted to see if I could find another node with a higher charge . These were 5 shot groups from 41gr to 42.5gr in .5gr increments with 178gr A-Max

These loads are over max load compared the the Hornady 9th book . I do not recommend anyone load over max charge .

I did not have any pressure issue and 42.5gr shot pretty good .

The problem was gone . Only one load had the first shot slower and that was by 7fps . Everything about the the velocities were better . ES never got above 35 and SD was in the teens .

I do have a couple thoughts though . Could this consistency have come from the case now being more full . I was a little surprised I could put 42.5gr of 4064 in the case and not have any compression . The bullet may have been touching the powder but at a glance I'd say they were not compressed .

What about the round robin method . Could that have been what caused the changes . Right about now I feel I may have changed to many things at once to know what made the biggest impact .

RaySendero · February 2, 2014, 12:38 PM

If single loading eliminates the problem - That's an important clue!

The 1st round is not experiencing the recoil that the last 3 are in the magazine. So, could be either the powder or the bullet (or both) are being rearranged by the recoil.

Easy to check the bullet - Measure the overall length of 2 rounds, Put these 2 in mag; Fire one; Take the one left in mag out and measure the OL. Compare if it has changed with the recoil.

Jimro · February 2, 2014, 02:13 PM

Metal God,

Were velocities closer to the 20fps slower numbers, or closer to the previous average numbers?

Jimro

Metal god · February 2, 2014, 03:51 PM

I believe I've ruled out bullet set back . I do recall taking my comparator to the range to check that very thing . If I remember right ( notes not in front of me ) I was not getting any bullet set back or movement .

Unfortunately I only shoot one 8 shot sting with my confirmed load . I did put that through the chrono but did not right it down . They were all shot consecutively to foul a very clean barrel . All I remember about those velocities was the problem did not happen on either 4 shot strings . The other thing was those first 8 shots of the day were also my smallest group of the day .88 moa @ 100yds . lol 8 shot group shot .88 moa .

I wish I wrote those down now . I was only looking to see if the 1st and 5th shots were slower and was thinking the data would not be reliable do to the fact the barrel was squeaky clean to start with . I did shoot those from the mag but did shake the ammo box up as well as drop the full mag on the bench from about 5" to loosen up the powder in the case .

**Unclenick** · February 3, 2014, 05:05 PM

Now you have to go back and not shake or drop anything and see what happens? Also sounds like either your original load was the best one you tried, or your gun doesn't like its barrel too dirty.

January 15, 2014, 08:28 AM	#51
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,061	I'll be interested to hear how the single loading goes. Another thing you could set up to try is backing the load down maybe 5% and working up to same velocity with a magnum primer. Magnum primers can sometimes swamp out ignition variation by brute force where the powder isn't snug in the case. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

February 2, 2014, 11:52 AM	#52
Metal god Senior Member Join Date: April 10, 2012 Location: San Diego CA Posts: 6,875	Went to the range yesterday . What I did was single shot loading and pulled the rifle in pretty tight to my shoulder . I also took the whole box of reloads and shook it up and turn it upside down to loosen up the powder in the case before loading the rifle . I should add that these test were of new loads of the same components and I shot the groups in a round robin way . I shot one shot of each load at a time letting the barrel cool completely between each shot .. My good load is/was 40.3gr of IMR 4064 . I wanted to see if I could find another node with a higher charge . These were 5 shot groups from 41gr to 42.5gr in .5gr increments with 178gr A-Max These loads are over max load compared the the Hornady 9th book . I do not recommend anyone load over max charge . I did not have any pressure issue and 42.5gr shot pretty good . The problem was gone . Only one load had the first shot slower and that was by 7fps . Everything about the the velocities were better . ES never got above 35 and SD was in the teens . I do have a couple thoughts though . Could this consistency have come from the case now being more full . I was a little surprised I could put 42.5gr of 4064 in the case and not have any compression . The bullet may have been touching the powder but at a glance I'd say they were not compressed . What about the round robin method . Could that have been what caused the changes . Right about now I feel I may have changed to many things at once to know what made the biggest impact . __________________ If Jesus had a gun , he'd probably still be alive ! I almost always write my posts regardless of content in a jovial manor and intent . If that's not how you took it , please try again . Last edited by Metal god; February 2, 2014 at 04:03 PM.

February 2, 2014, 02:13 PM	#54
Jimro Senior Member Join Date: October 18, 2006 Posts: 7,097	Metal God, Were velocities closer to the 20fps slower numbers, or closer to the previous average numbers? Jimro __________________ Machine guns are awesome until you have to carry one.

February 2, 2014, 03:51 PM	#55
Metal god Senior Member Join Date: April 10, 2012 Location: San Diego CA Posts: 6,875	I believe I've ruled out bullet set back . I do recall taking my comparator to the range to check that very thing . If I remember right ( notes not in front of me ) I was not getting any bullet set back or movement . Unfortunately I only shoot one 8 shot sting with my confirmed load . I did put that through the chrono but did not right it down . They were all shot consecutively to foul a very clean barrel . All I remember about those velocities was the problem did not happen on either 4 shot strings . The other thing was those first 8 shots of the day were also my smallest group of the day .88 moa @ 100yds . lol 8 shot group shot .88 moa . I wish I wrote those down now . I was only looking to see if the 1st and 5th shots were slower and was thinking the data would not be reliable do to the fact the barrel was squeaky clean to start with . I did shoot those from the mag but did shake the ammo box up as well as drop the full mag on the bench from about 5" to loosen up the powder in the case . __________________ If Jesus had a gun , he'd probably still be alive ! I almost always write my posts regardless of content in a jovial manor and intent . If that's not how you took it , please try again .

February 3, 2014, 05:05 PM	#56
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,061	Now you have to go back and not shake or drop anything and see what happens? Also sounds like either your original load was the best one you tried, or your gun doesn't like its barrel too dirty. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

February 2, 2014, 12:38 PM	#53
RaySendero Senior Member Join Date: August 23, 2010 Location: US South Posts: 857	If single loading eliminates the problem - That's an important clue! The 1st round is not experiencing the recoil that the last 3 are in the magazine. So, could be either the powder or the bullet (or both) are being rearranged by the recoil. Easy to check the bullet - Measure the overall length of 2 rounds, Put these 2 in mag; Fire one; Take the one left in mag out and measure the OL. Compare if it has changed with the recoil.