Mag primers

[lead chucker]

I would like to know how much should a guy reduce his load when using small federal mag primers in a 9mm? I don't have any small pistol primers except a brick of mag primers. I also have to seat the bullet a little deeper with powder coating. My bullet is a 120 gr that actually come out to 128 gr after powder coat. I have allot of unique powder and was thinking 3.6 gr for starters. I will be shooting this in a S&W M&P shield 2.0. What do you guys think?

[Winger Ed.]

Same thing happened to me. As primers dried up, I took what I could get.
I got a brick of CCI SPMag primers and needed to load some 9mm 120 cast.

I work out of the Lyman book, and for the powder I was using, I went right in the middle between Minimum and max. loads.
I haven't done a lot of scientific research on it, but they work fine.
I don't powder coat, but I think you'll be OK doing the same thing.

For the Smith, you could probably gas 'em up a bit more.
For me, if its accurate, and the steel plate falls down, I call it good.

[lead chucker]

Thanks for that Winger. I just don't want a stuck bullet with that light of a load but in that short barrel not too concerned. I also have a Kelltech sub 2000 and would not want a stuck bullet. I have a few 9mm guns and you know how it is. you would like one load to work in all of them which usually doesn't happen. Just trying to be safe.

[lead chucker]

Using the powder coating stopped all my leading issues. I tried every thing and my 9mm pistoles would lead the barrel except the sub 2000. I size all my 9mmto.358

[Winger Ed.]

. Just trying to be safe.

That's a good idea.

The folks that do all the testing & such seem to do it well.
I've never had any problems with anything starting off with minimum powder charges.
The only ill effect I've noticed is sometimes a minimum charge in a automatic won't kick it open far enough
to grab & chamber the next round.

Rumor has it that mag primers are a bit hotter, and the cup is a bit thicker than standard.
Then ya get to Winchester that has theirs labeled for standard or magnum loads.

In your situation, I'd load a few with 'middle of the road' powder weights, test 'em, see what ya got,,,, then work up or down from there.

[lead chucker]

I have used small rifle primers for my 9mm and they work but some times you get a miss fire and if you hit it again it will go off. My Kelltech does it some times. I have heard the small rifle primers have thicker cups so you need a harder strike. I have allot of small rifle primers. I use them in my 223 and 300BO

[lead chucker]

I'm going to the range tomorrow and going to do some testing and have some fun. The Unique powder i got was from my neighbor he sold me 2.5 pounds for $40.00 it was in the old fiber cans i tried some in my 45 acp and it still worked He used it in shot guns back in the day and doesnt have a use for it any more. I thought it was a good deal. Powder and primers dont even exist any more where i live.

[243winxb]

I been using Wspm primers. The 4.1 Unique is Speers starting load for 125 lead. I fired 4.3 grs. Maximum is 4.5. Tested 3 other powder, 2/10 grs below maximum, no issues. My cast diameter is .3568" Lee 356-120-TC. COL 1.045" for Taurus G3C.

https://www.speer.com/reloading/handgun-data.html

[Petander]

No issues here with Magtech SP mag primers in 9 mm.

[fa38]

I have shot SP mag and small rifle in several handguns. They don’t work in my Rem R51 or my S&W 638. Hammer and striker springs to weak. They work in two 1911 9mms and my Smith 14 38. and the L frame .357.

[mdi]

Reloading 101; Any time there is a compoment change, do another load work up. Start fresh with new components...

[JohnH]

Super Vel did a video on this a while back https://www.youtube.com/watch?v=NGVRGsoOr6k

[Larry Gibson]

I would like to know how much should a guy reduce his load when using small federal mag primers in a 9mm? I don't have any small pistol primers except a brick of mag primers. I also have to seat the bullet a little deeper with powder coating. My bullet is a 120 gr that actually come out to 128 gr after powder coat. I have allot of unique powder and was thinking 3.6 gr for starters. I will be shooting this in a S&W M&P shield 2.0. What do you guys think?

You'll find the answer here; https://castboolits.gunloads.com/showthread.php?423061-9mm-with-SP-and-SR-primers-psi-tests

Bottom line 3.6 gr unique will produce only so much pressure under a given bullet regardless of the primer used.

[Hanzy4200]

Don't load to max. That's all folk!

[ioon44]

Reloading 101; Any time there is a component change, do another load work up. Start fresh with new components...

This is the best advice, I use mag SP and SR in my 9 mm's and sp .45 but always do a load work up.

[tankgunner59]

I haven't done the conversion in pistol primers, but I did it a few years ago with LRP's. I bought a brick of LRP's from our LGS that turned out to be a large rifle standard primer box with 10 flats of LRMP's. I reduced the powder start charge, I believe Reloader 17, by 1 grain and fired 5 rounds. Resulting in no difference in any aspect. Sorry I don't still have the numbers I recorded but in my opinion if you don't use the max charge you should be fine. Incidentally, I have never needed to go max charge on any data to get the best results.

[jimlj]

I don’t load to max loads. I have been using SP, SPM and SR primers interchangeably with no issues in any of my 9mm’s. l’m using a Lee 358-125 rf powder coated boolit, sized .357 over 3.4gr Unique. YMMV

[Markopolo]

Leadchucker, looks like its about time to make a trip to anchor town... if the ferry is running u might be able to stock up on the road system?

[lead chucker]

I had a friend in Anchorage last weekend and no powder or primers any where.

[fredj338]

If you are loading at max, everything matters & you should reduce the charge & work back up. THis includes bullet changes, OAL changes & even case brands. Having said that, if your loads are midrange & below, a mag primer isnt changing much. Also powders matter. I have found faster powders dont really care what they ignite with, slower powders do benefit from hotter primers. With my midrange ammo across many calibers, I plug & play my primers.