100fps Drop - New Batch Primers???

[Tribe]

300wm, 76 H1000, 210vld

Everything identical.... noticed my dope took a dump... seems to be around 90-100fps slow (my chono is not currently behaving, so I can't test... but I don't trust those things too much anyway).

It seems to coincide around the time I started into a new batch of primers, but I can't say for sure... it is however, my very best SWAG at the moment...

Would that be out of the relm of reality... both CCI Magnum, just different batches.

 

[Guest]

Re: 100fps Drop - New Batch Primers???

I've found the difference between a std an mag primer can be, as much as 250 fps depending powder used, an how much of it the case holds.

 

[Fuzzball]

Re: 100fps Drop - New Batch Primers???

"..seems to be around 90-100fps slow (my chono is not currently behaving, so I can't test... but I don't trust those things too much anyway)."

Huh? I'm confused! IF your "chono is not currently behaving, so I can't test... but I don't trust those things too much anyway" then how can you know they are slow? Or if you don't trust it how can you know they were previously faster, or even if it's changed at all? And even an ambient temperature change could make that small a difference.

 

[Tribe]

Re: 100fps Drop - New Batch Primers???

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Fuzzball</div><div class="ubbcode-body">"..seems to be around 90-100fps slow (my chono is not currently behaving, so I can't test... but I don't trust those things too much anyway)."

Huh? I'm confused! IF your "chono is not currently behaving, so I can't test... but I don't trust those things too much anyway" then how can you know they are slow? Or if you don't trust it how can you know they were previously faster, or even if it's changed at all? And even an ambient temperature change could make that small a difference.</div></div>

Rounds on target.....

 

[Tribe]

Re: 100fps Drop - New Batch Primers???

Gunfighter... Yeah, it blew me a way, the first time I realized how big of a difference brass weight/capacity - velocity... can be from lot to lot, of the same manufacturer.... I suppose I've naively figured primers to be far more consistent between lots...

But as stated, the only thing changing in these loads, that I could put my finger on, would be the primers.

 

[Guest]

Re: 100fps Drop - New Batch Primers???

There should not be a major spread within any lot of primers.

I sounds like someone may have boxed them wrong or something. In my 300wm I use 210m's w/ Re-22 an 25 with 215M's the spread an SD is bigger. The thing I like about Federal is they color code the primer so there's no mistaking which they are, plus you can tell if the tray has every been slid from the box. Most others you could change trays and unless the guy has a chrony, shoots long, or knows how his gun recoils, he won't know one way or the other.

If your looking for hot, Winchester LR Mags will lite anything no matter the temp.

 

[Tribe]

Re: 100fps Drop - New Batch Primers???

It IS a different lot of primers......?

May be giving some Winchesters a try.... thanks much.

 

[ranger1183]

Re: 100fps Drop - New Batch Primers???

Try Wolf or Tula primers. Good stuff. If you need some, I'll drop some off.

 

[Tribe]

Re: 100fps Drop - New Batch Primers???

Thing is... I'm not sure it's the primers at all, just trying to establish if merely cracking into a new lot of primers falls into a reasonable range of possibility for my velocity drop.

I'm just trying to figure out, why my loads have suddenly experienced a significant velocity drop, when nothing in the recipe has changed... and ambient temps of late, have been 20-30 degrees hotter if anything...

 

[ranger1183]

Re: 100fps Drop - New Batch Primers???

In theory, the barrel changes with every shot. If I had your rifle, I could send it to QC to inspect the throat and bore. That's a quick visual inspection to see if any obvious damage has occurred. (Man is it ever great to have a bunch of cool tools to work with.