Conflicting info, now I'm not so sure. (Primers)

[USSR]

All load manuals will tell you that if you change any component you’re to drop down and work back up.

That's a CYA statement made by the load manual's lawyers. Makes perfect sense, and if I had such a business I would make that statement myself. HOWEVER, in the real world, when using light loads and making such a change, common sense tells you that it won't make diddly squat difference pressure-wise.

Don

[Burnt Fingers]

I’m not missing anything. All load manuals will tell you that if you change any component you’re to drop down and work back up. I realize that very few people do this. But that’s there prerogative.

That's a CYA statement made by the load manual's lawyers. Makes perfect sense, and if I had such a business I would make that statement myself. HOWEVER, in the real world, when using light loads and making such a change, common sense tells you that it won't make diddly squat difference pressure-wise.

Don

So let's say I'm loading 3.6 gr of Clays under a 200 gr SWC. I switch from Winchester to CCI primers. Am I supposed to drop BELOW the recommended starting load and work back up? 3.6 gr Clays is the starting load.

[USSR]

Great point, Burnt Fingers.

Don

[fredj338]

I’m not missing anything. All load manuals will tell you that if you change any component you’re to drop down and work back up. I realize that very few people do this. But that’s there prerogative.

Yeah so? Its CYA. They are saying if your load is max & you swap, then drop 10%. I've done a lot of reloading, well over 400K rds in 40y & several wildcats with no data for. A 10% drop is quite a lot. From max it is reasonable, from midrange, out of context. Everything has to have a context. So you did miss that.

[fredj338]

So let's say I'm loading 3.6 gr of Clays under a 200 gr SWC. I switch from Winchester to CCI primers. Am I supposed to drop BELOW the recommended starting load and work back up? 3.6 gr Clays is the starting load.

Just my point. No, its a starting load, why would you drop a starting load for any change in components?
Again, if you are at midrange or below, swapping any component wont move the pressure needle much. A diff case brand, bullet shape or primer wont likely affect anything. The exception would be something like 150gr SWC & then trying to sub a 148gr WC. That might get interesting.

[HangFireW8]

I have the same observation... Dropping 10% means from the max load, but the manuals don't make that clear. Have to throw in the caveat, don't drop that much with H110/W296, but then one should already be using a mag primer.

[greenjoytj]

Ever notice when you feel like doing a little reloading you never have the components specified in the load recipe you want to try.
The case is different, the primers can't be found, the bullet used is unobtainable, the only thing you have on hand is the powder.
And it not the same lot used in the manuals recipe.
Start low work up. But I suspect most start in the middle range an decide which way to go after the test firing.

[Hickory]

While on tour of the CCI plant in Lewiston ID some years ago I asked our guide, who was a supervisor there what was the difference between their standard primer and their magnum primer.
He said that the priming mixture in the magnum primer was formulated to burn several milliseconds longer than the standard primer.
Testing was done with several miles of [det-cord] primer mix run out into a long circle with an electric timer on each end to measure the time it took to burn x # miles of primer mix one end to the other.

[Cosmic_Charlie]

While on tour of the CCI plant in Lewiston ID some years ago I asked our guide, who was a supervisor there what was the difference between their standard primer and their magnum primer.
He said that the priming mixture in the magnum primer was formulated to burn several milliseconds longer than the standard primer.
Testing was done with several miles of [det-cord] primer mix run out into a long circle with an electric timer on each end to measure the time it took to burn x # miles of primer mix one end to the other.

Very interesting. Thanks!

[1hole]

There is a bit of conflicting info on this site. Some say reduce the load by 10% and work it back up, others say there is really no difference and say load and shoot. .... I load .38 special using 148 to 155 grain bullets lubed with Tac-1 and 3.1 grains of Bullseye. That is a very mild load and it don't rattle my wrist at all and can go through a hundred rounds easily. If it ain't broke, there is no need to tinker with it unless the primers can make a difference.

First, the 10% reduction you mention is understandable legal boiler plate for loading book makers. It's meant for those who are loading up around the ragged edge of a KABOOM. That reduction is not needed for low or mid-range charges, you are (effectively) already at or below a 10% reduction.


"Can primers make a difference?" Sure, in fact everything can and does make a "difference". So your question becomes, "Does this change matter enough to matter?" I don't believe using mag primers in your light loads are enough different to matter for safety but, if your accuracy degrades it would be good to experiment with your charges a tad.

[454PB]

I've found that CCI 550 primers can be hard to ignite in striker fired pistols. In a gun that is hammer fired, it's easy to give it a second try, striker fired it's a PITA. Same gun, same load with CCI 500 primers fired 100%.

[robg]

primers are £45x1000 over here