Loading GP 90 from GP 11
- Thread starter Craig0ry
- Start date
Not quite doing that and don't think I would actually try doing that 
I make GP 90-like rounds for my Schmidt Rubin using 7.5×55 Swiss brass trimmed down to 53.5 mm and then sized in Lee 7.5 Swiss dies. I load cast bullets using 30-40 Krag cast bullet load data from the Lyman cast bullet book.
I keep meaning to cast the chamber in my Schmidt-Rubin to see if the trimming is really necessary but I've not gotten around to doing the casting.
Gungeek -- a guy out in Nova Scotia -- talks about loading for this round in this video: https://youtu.be/eJEm6xh-tA0
Hope this sort of helps.
I make GP 90-like rounds for my Schmidt Rubin using 7.5×55 Swiss brass trimmed down to 53.5 mm and then sized in Lee 7.5 Swiss dies. I load cast bullets using 30-40 Krag cast bullet load data from the Lyman cast bullet book.
I keep meaning to cast the chamber in my Schmidt-Rubin to see if the trimming is really necessary but I've not gotten around to doing the casting.
Gungeek -- a guy out in Nova Scotia -- talks about loading for this round in this video: https://youtu.be/eJEm6xh-tA0
Hope this sort of helps.
Not quite doing that and don't think I would actually try doing that
I make GP 90-like rounds for my Schmidt Rubin using 7.5×55 Swiss brass trimmed down to 53.5 mm and then sized in Lee 7.5 Swiss dies. I load cast bullets using 30-40 Krag cast bullet load data from the Lyman cast bullet book.
I keep meaning to cast the chamber in my Schmidt-Rubin to see if the trimming is really necessary but I've not gotten around to doing the casting.
Gungeek -- a guy out in Nova Scotia -- talks about loading for this round in this video: https://youtu.be/eJEm6xh-tA0
Hope this sort of helps.
What mold are you using?
This Wikipedia page is pretty good for general information:
https://en.wikipedia.org/wiki/7.5×55mm_Swiss
In the Specifications table note the different lenghts for GP90, GP90/03, GP90/23, and GP11 --
https://en.wikipedia.org/wiki/7.5×55mm_Swiss#Specifications
Here's another video for loading the round with sample load data in the description --
https://youtu.be/a5JdJkRb0yA
What rifle are you loading for? Do you have 7.5 Swiss dies?
Tradeex has 7.5 Swiss brass but it's getting a little expensive. It was $75 per 100 cases the last time I bought some; it's now up to $90 per 100 --
https://www.tradeexcanada.com/content/75x55-swiss-brass-prvi--
The brass seems to hold up to repeated reloading -- I've reloaded mine at least six times with no signs of it wearing out so far. I've reloaded both new PPU brass and brass from fired PPU factory rounds. The brass is almost the cost of a GP11 round but it does hold up.
Eaglelord17
CGN Ultra frequent flyer
- Location
- Sault Ste. Marie
Do not do this if you value your life. There is a lot that can go wrong here and for cheaper ammo (not even that much cheaper) I personally wouldn't do it. The 1889 isn't a strong action, not much room for error and guessing the right amount of powder for the round definitely isn't a smart way to do things.
If you want to shoot a 1889 buy reloading gear. Some will require the brass to be cut back, my personal 1889 doesn't and can use standard length 7.5x55 brass. My personal load is 32grns of IMR 3031 under a 220grn sierra round nose .308 bullet.
If you want to shoot a 1889 buy reloading gear. Some will require the brass to be cut back, my personal 1889 doesn't and can use standard length 7.5x55 brass. My personal load is 32grns of IMR 3031 under a 220grn sierra round nose .308 bullet.
I think you could use any 308 mold of suitable weight but I am using a NOE mold designed especially for the K31:
http://noebulletmolds.com/NV/product_info.php?products_id=344&osCsid=in0bt7iib83c4bepfvcr9c6uk7
Ordering from NOE is easy and they ship to Canada without any problems.
Based on my experience, the typical charge weight for "factory" GP11 is 50.0 grains (small extruded powder - finer than IMR4350)
I built a few rounds of GP90 "plinking ammo" for a friend to test his Model 1889 (if my memory serves correctly). I looked up my notes and ran the numbers through QuickLOAD to confirm them.
PM me if you want the data files...
Chambers and throats tend to be "spacious" in the 1889's to make room for the original paper patched bullets.
I find there is no need to trim the 55mm cases down to 53.5mm, a time saver. Necks will expand. Anneal the necks.
Casting is out the question for me, so I just use jacketed bullets. 178gr A-max works very well.
My GP90/M1889 load rule is charge should be 80% of the recommended Max load for GP11, with that same powder and bullet weight.
Can also use 80% of .308 load with whatever powder you have with the same weight bullet.
.308W is smaller case capacity so pressure drops in the larger 7.5x55 case.
Swiss use for all intense and purposes the same powder as RL-17
Yes 50gr in GP11 with 174 gr bullet.
From Alliant:
RELOADER'S GUIDE
Alliant Powder Reload Recipes
Caliber-Bullet-Case Minimum OAL"-Bbl Length-Primer-Powder-Charge Weight gr-Velocity fps
Notes
308 Win. Speer 150 gr BTSP Federal 2.8 24 Fed 210 Reloder 17 50 2,763 -
308 Win. Speer 165 gr BTSP Federal 2.8 24 Fed 210 Reloder 17 50 2,739 -
308 Win. Speer 180 gr BTSP Federal 2.8 22 Fed 210 Reloder 17 48.7 2,641 -
7.5x55 load tables:
http://theswissriflesdotcommessageboard.yuku.com/topic/9041/75x55-Load-Tables
BTW: GP11 bullets are very hard to pull. Using a hammer type bullet puller is not easy. I use a collet style puller when needed.
If you can reload, do it.
I would recommend using a faster powder than RL-17 for the 1889 GP90, to seal the chamber somewhat better to avoid sooty necks.
I have used Varget and H4895.
I find there is no need to trim the 55mm cases down to 53.5mm, a time saver. Necks will expand. Anneal the necks.
Casting is out the question for me, so I just use jacketed bullets. 178gr A-max works very well.
My GP90/M1889 load rule is charge should be 80% of the recommended Max load for GP11, with that same powder and bullet weight.
Can also use 80% of .308 load with whatever powder you have with the same weight bullet.
.308W is smaller case capacity so pressure drops in the larger 7.5x55 case.
Swiss use for all intense and purposes the same powder as RL-17
Yes 50gr in GP11 with 174 gr bullet.
From Alliant:
RELOADER'S GUIDE
Alliant Powder Reload Recipes
Caliber-Bullet-Case Minimum OAL"-Bbl Length-Primer-Powder-Charge Weight gr-Velocity fps
Notes
308 Win. Speer 150 gr BTSP Federal 2.8 24 Fed 210 Reloder 17 50 2,763 -
308 Win. Speer 165 gr BTSP Federal 2.8 24 Fed 210 Reloder 17 50 2,739 -
308 Win. Speer 180 gr BTSP Federal 2.8 22 Fed 210 Reloder 17 48.7 2,641 -
7.5x55 load tables:
http://theswissriflesdotcommessageboard.yuku.com/topic/9041/75x55-Load-Tables
BTW: GP11 bullets are very hard to pull. Using a hammer type bullet puller is not easy. I use a collet style puller when needed.
If you can reload, do it.
I would recommend using a faster powder than RL-17 for the 1889 GP90, to seal the chamber somewhat better to avoid sooty necks.
I have used Varget and H4895.
Last edited:
NB.nagantsniper
CGN frequent flyer
- Location
- northern nb
very interesting info im starting reloading for my 1889 swiss will use this info .
I found that out the hard way with my Model 1889 rifle after assuming, something a person should ever do when it comes to reloading, that all 7.5X55 dies would work OK with all of the different models.
