280 Ackley primers, standard vs magnum

letrbuck

WKR
Joined
Jun 5, 2017
Location
NW Wyoming
280 AI loaders, what primer do you use and why? Have you tried the same load and just switched between primer type? What did you notice as far as pressure, accuracy, and velocity?
 
I found during a workup with Hammer bullets that I needed about 1.5 grains more powder to get the same speed when using a CCI250 vs a CCI200.
 

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I use CCI200 because that's what I have most supply of and am not shooting over the 60-65gr range of extruded powder. I've never tested it personally but I have read about loads reaching pressure much faster using magnum primers in some of the standard LA cartridges.
 
I found during a workup with Hammer bullets that I needed about 1.5 grains more powder to get the same speed when using a CCI250 vs a CCI200.
The info written on the targets in your pics show the CCI250 getting 40 fps more velocity with 1.5 gr more powder, not the same velocity. What am I missing?
 
I found during a workup with Hammer bullets that I needed about 1.5 grains more powder to get the same speed when using a CCI250 vs a CCI200.
35WhelanAI said
The info written on the targets in your pics show the CCI250 getting 40 fps more velocity with 1.5 gr more powder, not the same velocity. What am I missing?
I noticed that too and to me that one data point seems insufficient to support the conclusion drawn. There is only a 40 fps increase with an additional 1.5 gr and I would expect more than that, but its also possible a plateau was reached. RAZ may have more data to support his conclusion and only showed the 2 targets as an example.
 
280 AI loaders, what primer do you use and why? Have you tried the same load and just switched between primer type? What did you notice as far as pressure, accuracy, and velocity?
I have ran a 280 AI for about 15 years and some really old reloaders told me that using a magnum primer will help burn all the powder in the long case and it's a little more consistent
 
I mostly use mag primers just in case I need the rifle or revolver to fire in the dead of winter. -40° and bullets can dribble out the end of the barrel with standard primers.
 
I got more consistent velocities with LR primers in SAUM cases a while back and haven’t tried a LRM primer for years in the short mags. I’d not hesitate to use either and would only really favor a LRM if you’re stuffing the case full of slow burning ball powder.
 
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