Loading 5.7x28

[mallc]

Just ran first 50 reloads through my new FN FiveSeven (only 100 rounds of factory through it). Case trim and OAL carefully controlled with 4.9 to 5.0 gr True Blue (low end of Ramshot specs) and 40 gr Nosler BT. The report is quite a bit louder than factory and rack was a bit faster; but, the brass seems healthy with no signs of over pressure.

Question:

I had a couple of misfeeds at the magazine and the slide failed to lock back on last round of one mag. With other calibers I'd say the problems were caused by low charge rate and I probably need to kick it up a few grains. Given the low total rounds on this firearm and the eccentricity of the 5.7x28 round, I thought I'd ask your opinions before proceeding.

Thanks for replies!

Scott

 

[cheygriz]

See how it works after a "break-in" period of about 250-300 rounds.

 

[dsv424]

That load appears a bit low. For a 40g. Hornady Vmax I use 5.7g. True Blue with an OAL of 1.580. I'm using this in a AR-57 and it works great. You may want to visit the five-seven forum for more data on reloading this caliber. I use this recipe for Nosler BT and it works great also. Other powders that work well with this caliber are AA-7 and HS-7

 

[ehryk]

one of my favorite plinking loads with my FsN is 5.8 grains VV 3N38 with any 40 grain ballistic tip. This is pretty much an identical twin to the SS197. I have done no reloading with True Blue, so I can't safely make a comment there.

The main signs of pressure you need to look for with the 5.7x28 are primer cratering, case mouth denting, heavy ejector marks and very heavy shoulder movement. The reason I say very heavy is that by design, the shoulder moves a LOT more than any other round I have ever loaded for. I am sure you have noticed this with factory loads though.

 

[Walkalong]

Your load is light. It needs bumping up.

True Blue 35 HDY V-MAX FB 5.7 1,923 6.4 2,007 45,500 1.491
True Blue 40 SIE SPH 5.6 1,813 6.3 1,961 45,300 1.456
True Blue 45 SIE SPH 5.4 1,700 6.1 1,858 45,600 1.490

Longer Bullets
True Blue 40 HDY V-MAX 5.0 1,660 5.6 1,850 48,800 1.580
True Blue 45 SIE SPT 4.8 1,562 5.4 1,725 46,200 1.580

From Ramshot PDF

The shoulder is where the case fails. It gets blown forward when fired and then pushed back .020 to .040 or so. It's a bit alarming to someone who has experienced normal shoulder set back loading all these years. The first thought is something is wrong, but it isn't.

FiveseveNForum - I posted there some when I was reloading 5.7 X 28.

 

[mallc]

Thanks All

Thanks for helping. - Scott