So, I have been able to pick up some Magnum Small Rifle primers. Does a person need to lighten powder load from regular primers? Shooting in AR-15, 5.56. It appears some recommend magnum primers in AR's because they have thicker metal and are less prone to a slam fire. Any help is appreciated!

Rule of thumb FWIW, subtract 1-1 1/2 grn for magnum primer to start, if not called for.

Consult a manual.
Getting reloading info on a forum isn't advisable.

Brian, how much are limiting you guys at the Scheels in st cloud? Still a couple hundred per person?

I managed to pick up 6400 of the CCI 450s this week, and 1200 Federal 210s LRP.

The Scheels in Fargo is only allowing 200 yet per person, others are allowing 1000.

200 here, also. They seem to have a bunch and stock a couple thousand each day. Get there early with friends and you can get a few.

Like bucks&bears said consult a manual. More often than not when magnum primers is called for in a nonmagnum caliber it is powder specific not case specific. Some powders are more difficult to ignite than others.
The reduction in powder should be on a percentage basis not a set grn number. For example 1 gr reduction in a 300 RUM = 1/100 whereas 1gr in a 5.56 maybe 1/25 or in other words 1/100= 1% and 1/25= 4%.
These can be trying times when you can’t just go get the exact components called for in the book. Then carefull extrapolation and a reduction of 5% from the starting load maybe your only option. And yes slam-o-matics sometimes call for a tougher primer for the reason you mentioned.

I stopped at 4 scheels on the way home from KS, three out of the 4 allowed 1000 at a time, I had my daughter with. We did well.

Scheels in Fargo today was loaded up on 9mm. $16 for 50 i believe it was, they were allowing two boxes. Kid said they had a ton.

there was a very good video posted here by a reloading company , they used their equipment to help answer the question the did CCI small pistol, small pistol magnum and small rifle they all had well with in spec the same pressure they really only had a thicker up so that they could take more back pressure.

not that dropping down 10% and working up is ever really bad advice.


the CCI military primers sold in the white box are just that magnum cup thickness.

what price are they selling per thousand

In the last few weeks I've bought CCI 450s for 45, CCI 400s for 40, Federal 210s for 40.

agreed!

THIS

Not everything is in a manual. It is basic information only. The advice to reduce the charge and shoot the rifle, gradually increasing the charge and looking for high pressure signs, is GOOD advice. Like it or not if you want to keep shooting and availability of ammo and components doesn't change, your going to have to be flexible.

https://www.youtube.com/watch?v=UxIach0t2dY

P.S. the new Lyman book has a powder burn rate chart on the last page. you can compare powder burning rates. Can be handy if there is no data for the powder you have.

Here is a good online chart

https://loaddata.com/Article/BurnRateCharts/Powder-Burn-Rate-Chart-NEW/159

Faster powder use less and slower powder will use more.

wildcatters have been working up loads by checking primers for high pressure indications for at least a century

Helped a buddy work up a load for his 375 R.U.M. last week. he had a two boxes of 260 grain nosler partitions and a 5 pound jug of Reloder 25. Had a box of 1000 CCI LRMP. We stopped at 105 grains of powder. Powder was at the bottom of the case neck. (full is what you want if you do any testing. if its not 80% or so full when you start seeing that dimple around the primer, its not safe. case MUST be close to full for rifles)

Shot this railroad plate at 25 yards. At 100 yards groups are the size of a quarter. I'd say it will work just fine.

Thanks for the help. I have three loading manuals and they do not cover this. I know there is one powder out there with load data using mag primers, BLC-2. Unfortunately, I do not have any, so I thought I would pose the question here and a few other loading sites. Again, appreciate the input!

If you go to Hodgdons reloading site you will see that the max load of H4831 is 101 grains. If you look at the burn rate chart i posted you can see that Reloder25 is slower. So we started at 100 grains of Reloder 25. The bolt handle moved freely after the shot, it extracted nicely, there was no dimple around the firing pin dent or a flattening of the primer. So we increased the charge, 1 grain at a time. At 106 grains there was a very slight dimple around part of the primer. Went back to 105 and there was not any dimple.