16ga.com ~ View topic - Non-Tox choices for an old gun? UPDATE: ---Tested Loads----

Joined: 27 Oct 2017 Posts: 80 Location: Joliet, IL

Indeed it does look perfect. Unfortunately I have time, equipment and supply constraints on this project - No source of Federal hulls, or primers. I did get some Unique and decided on that rather than Herco.

Anyway, I got my shipment today. I discovered that the Fio/Fio cut to 65mm, 1oz 7 1/2 , 19.5 Unique load found in the old 16ga Yahoo groups data does indeed shoot 1150 fps - despite the fact that I substituted a 65mm roll crimped hull in for a 70mm star crimp. All good there, and that's where my plan fell apart.

My intention was to shoot for 1,200 fps, substitute in 390 grains of bismuth shot, then double check fps. Unfortunately my Magnetospeed V1 has extreme difficultly picking up bismuth shot loads - and they are too damned expensive to spend 10's of rounds adjusting set off height and trigger sensitivity. I wasted 5 20ga Bismuth shells searching for a reasonable custom trigger setting.

I shot 2 rounds of Bismuth 16ga custom loads:

Fio cut to 65mm
Fio primer
20 grains Unique
SG16 wad
390 grains No. 6 Bismuth (As it measured very close to lead stack height)
Ovr Shot Card
Roll Crimp with slight compression

Both gave what I believe are 100% garbage velocity readings on the Magnetospeed - 2,257 fps Rolling Eyes

, and 1,363 fps (maybe, but seems very doubtful).

At this time I will probably give up trying to adjust the load further, pick 2 powder charges perhaps 19.5 and 20.5, send them in to Precision for testing and let the chips fall where they may.

As an aside I shot a number of RST No 8's over the Magnetospeed and those showed a very consistent 1,180 fps avg - right there at the 1,200 advertised velocity - bravo RST. The Magnetospeed V1 works well with lead shot loads - IF you use the short stand off rubber and let the wad scrap the bayonet a little.

Joined: 27 Oct 2017 Posts: 80 Location: Joliet, IL

Update with load tests from Precision Reloading

FIO hull - New - hand trimmed to 65mm - roll crimp with PRI roll crimp tool
FIO primer
SG 16 wad
390 grains - Bismuth No. 6 taken from Kent hulls
Unique Powder
________________________

19.5 grains Unique

AVG - 1,234 fps - 5,683 psi
STD DEV - 19 fps - 532 psi
EX SPR - 46 fps - 1,370 psi
_________________________

20.5 grains Unique

AVG - 1,262 fps - 6,022 psi
STD DEV - 21 fps - 220 psi
EX SPR - 50 fps - 490 psi
__________________________

My thought is to go with the 20.5 grain load. Despite slightly exceeding my target FPS this load appears to have a more stable burn with substantially less shot to shot variance in PSI, while still retaining very low PSI levels.

I am a bit confused by how low the PSI levels came back. I was expecting 8,000-9,000, not 6,000. But those are numbers I got. My concern would be low temp causing issues later in the season, assuming the testing is on the money.

Happy to e-mail anyone that wants the test sheets a copy. Just IM me with your e-mail address.

Joined: 04 Mar 2019 Posts: 1842 Location: Central ND

AKDan,

That load looks right.

For the most part when developing Bismuth loads you start with a lead load that is 1/8 oz. heavier than what you want to load with Bismuth.

That load looks correct, because of the SP16, it won't develop the chamber pressure like a Z2M16 or an SG-16.

Joined: 13 Oct 2015 Posts: 348

Good tested loads in update, well done. I'd load it up to 21.5 or 22 gr and go for 1325fps or so. No prob with pressure I'd say.

Joined: 27 Oct 2017 Posts: 80 Location: Joliet, IL

Joined: 04 Mar 2019 Posts: 1842 Location: Central ND

makintrax,

A very simple way to build a Bismuth load is to use 1/8 oz. less Bismuth in a tested lead shot load. I have never seen that not work and many times the pressure is lower with the Bismuth.

The load you built was a very nice mild 1 oz. lead load.

Factor in the roll crimp, Fiocchi primer, 7/8 oz. of Bismuth and the moderate amount of Unique powder and the chamber pressure was bound to be low.