muzzle velocity - brass brand

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JMack

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noted some velocity drop loading 7prc 1x fired brass to 2x fired brass, about 100 fps enough to cause misses at 500 yards.

Do any of you notice a difference when using premium grade brass like lapua or adg when on multiple firings?

My buddy had a Garmin chronograph and honestly if we didn't have that thing there I would have not noticed the drop in numbers I would have only left scratching my head as for the low/off target misses.
 
It may not be the brass.
What powder are you using, what temperature difference is there from when it was loaded and tested, what elevation?
Assuming it is caused by the brass is the least possible cause of this.
Have you changed ANYTHING from the previous load?

If all other components are the same, then it has to be the powder.

Cheers.
 
MagnumManiac said:
It may not be the brass.
What powder are you using, what temperature difference is there from when it was loaded and tested, what elevation?
Assuming it is caused by the brass is the least possible cause of this.
Have you changed ANYTHING from the previous load?

If all other components are the same, then it has to be the powder.

Cheers.
Click to expand...
That I know of nothing on components changed. I loaded them Friday evening it was definitely cooler than when I shot today maybe 15 degrees warmer this evening. Nothing extreme. Same primers same powder.
 
JMack said:
That I know of nothing on components changed. I loaded them Friday evening it was definitely cooler than when I shot today maybe 15 degrees warmer this evening. Nothing extreme. Same primers same powder.
Click to expand...
Which powder?
Unstable powder can swing this much near max pressure.

Cheers.
 
Happens a lot. Brass is being fire formed, stretched, etc. So i always make two loads, new brass versus once fired. Neck tension, how did you know it dropped 100 fps without a chrono?
 
100 fps is excessive for quality matched head stamped brass of the same lot number.
A slight temp swing won't do that, I never personally see that much variation during fire forming either.
I wont speculate on what's going on but I would look at my loading practices first.
JMack said:
any of you notice a difference when using premium grade brass like lapua or adg when on multiple firings?
Click to expand...
 
In some of my guns, I notice that much difference between virgin brass and already fired brass (that fits the chamber better).

I even have to change the load data to maintain the same accuracy. I load the virgin brass with one load, and fire formed (FL resize) with a different charge.
 
Read the OP's situation.
100fps difference between 1x fired and 2x fired. Not virgin to 1x fired.

No. I have never seen a 100fps drop between 1x and 2x fired brass.

Same bottle of powder?
Did you leave the powder open for a long period of time?
Same box of bullets?
Same primers?
Clean vs dirty barrel?
Shot angle? Flat vs up/down?
 
JMack said:
noted some velocity drop loading 7prc 1x fired brass to 2x fired brass, about 100 fps enough to cause misses at 500 yards.

Do any of you notice a difference when using premium grade brass like lapua or adg when on multiple firings?

My buddy had a Garmin chronograph and honestly if we didn't have that thing there I would have not noticed the drop in numbers I would have only left scratching my head as for the low/off target misses.
Click to expand...
Short answer is no, what powder are you using?
 
lancetkenyon said:
Read the OP's situation.
100fps difference between 1x fired and 2x fired. Not virgin to 1x fired.

No. I have never seen a 100fps drop between 1x and 2x fired brass.

Same bottle of powder?
Did you leave the powder open for a long period of time?
Same box of bullets?
Same primers?
Clean vs dirty barrel?
Shot angle? Flat vs up/down?
Click to expand...
4831sc

Dumped powder into chargemaster and proceeded to load 10 of each.

Everything else exactly the same.

Only difference was Hornady 1x vs 2x

The brass was shot out of same rifle prior.
 
lancetkenyon said:
Read the OP's situation.
100fps difference between 1x fired and 2x fired. Not virgin to 1x fired.

No. I have never seen a 100fps drop between 1x and 2x fired brass.

Same bottle of powder?
Did you leave the powder open for a long period of time?
Same box of bullets?
Same primers?
Clean vs dirty barrel?
Shot angle? Flat vs up/down?
Click to expand...
Ditto!
 
JMack said:
4831sc

Dumped powder into chargemaster and proceeded to load 10 of each.

Everything else exactly the same.

Only difference was Hornady 1x vs 2x

The brass was shot out of same rifle prior.
Click to expand...
I'd verify the electrical powder dispenser first against beam scale.
 

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