So I might be breaking the topic, but I have another gun Shadow 9mm and I talked about awhile ago in an old post. It's a 223/5.56 Stag Super Varminator. It has a huge barrel 24 inches long with a 1/8 twist.
Stag says it's half MOA gun. That wouldn't surprise me. Last time at the range I was getting 1 MOA about with factory green tip Winchester 5.56mm ammo. In the Stag half MOA tests they use 75gr HPBT match grade ammo from Sierra King.
I bought 75gr HPBT Hornady Match bullets with Ramshot Tac powder. I'm reloading these once fired Winchester pieces of brass.
I also bought Hornady Match factory ammo 75gr BTHP. They're like $1.25 a round which is insane. This could definitely be a money saver too reloading these, as reloads would cost half or less this much, even with reloading component costs now. I bought a couple boxes of the factory Hornady Match though just to see if I can beat it.
In any case, I've already got the Winchester brass trimmed to 1.75 inches chamfer deburred and the primer pockets and brass are clean. I'm sort of following the factory specs of the factory Hornady ammo first which is 1.75 inches brass with 2.25 inches COL. I was thinking I could get away with 2.255 .005 inches longer later for better ammo perhaps after I test this
In any case, I'm sort of having the same problem again with the 9mm. I think Ramshot Tac will be great for this, but I can't find load data for a charge for 75gr BTHP by Hornady. According to Gordon's and some googling in other forms I see 22grs for a good starting charge.
I'm thinking the magic is 22-23.5 grains Ramshot TAC. Any ideas on this one guys? Am I on the right track here?
https://www.ramshot.com/wp-content/uploads/2020/08/WesternPowdersHandloadingGuide8.0_WEB.pdf
On page 50 of the document itself, page 52 in PDF doccument. they have specific data for ramshot tac, and the 75g Hornady OTM bullets
When looking for a load, don't forget to check the bullet makers data, and the powder maker data.
My process for rifle data is this. load at the bullet makers recommended COL in this case 2.250. The max COL for the cartridge is also 2.260, and that is the max length to fit in the magazine and feed properly. You could seat to 2.260 however
too close to the lands can also increase pressure and cause pressure spikes, and again, does not necessarily increase accuracy. If a bullet manufacturer recommends a specific COL there is generally a reason for it. Typically for hunting guns you want a minimum of 0.020 off the lands for reliability and to prevent pressure spikes. Again, see the vides from Eric cortina, I liked them at the bottom again. closer to the lands is not always better, and IMHO is somewhat irrelevant.
I would then work up the load from start using westerns load data for this exact bullet combination.
Start 21.7g at 2582 FPS
Max 24.1g at 2820
So I would work up 1 round each. fire them. look for pressure signs. see how they act in your gun. Obviously stop if you start running into pressure signs you are not comfortable with. If I hit flowed for cratered primers I stop and back off.
21.7
22.2
22.7
23.2
23.7
24.1
after testing for pressure, I work back down, same increments, shooting groups of 7-10 over the chronograph looking for a good stable velocity window.
After I find a good velocity point. I do a seating depth test. I start at my COL. then work back in 0.003 increments. The only good way to do this is with a micrometer seating die in my experience. and the hornady bullet comparitor to measure.
so in this case, 5rnds each
2.250
2.247
2.244
2.241
2.238
2.235
2.232
2.229
what I look for is open groups, groups closing up, then opening up again. I select the smallest group. if i have 2-3 good groups i choose the one closest to the rifling. Since the rifling wears over time as the bullet gets farther away, it will still be in the sweet spot.
Last time I did this I took my TC Compass in 30-06 that would at best do 1.1moa, and typically did 1.5 to 2, down to 0.75moa, just by adjusting seating depth.
I don't care how far off the lands I am. Just that the bullets are coming out consistently. and that I can measure, from a point on the ogive, where I put them, so I can put them there again.
These 2 vids explain explain my bullet seating methodology.
Chasing the lands is STUPID! Don't do it.
https://www.youtube.com/watch?v=oRXlCG9YZbQ
Chasing the lands is STUPID: Part 2
https://www.youtube.com/watch?v=9FKq8Jj8YEI
That is how I do things, and why. It has worked well for me. Check from start to max for safety. Work back down to preserve as much velocity as possible while finding a good velocity window. lastly tune the seating depth to a consistent point in the barrels harmonics. There are lots of rabbit holes you can god down, and nuances to get into. I went down a LOT of them. In the end, after lots of fiddling, tinkering, and frustration, this is what has worked best for me.
Also here is a video from Johnnies reloading bench. I really enjoy his channel. he tests the Hornady 75g OTM with 19 powders, one of which is ramshot TAC.
https://www.youtube.com/watch?v=5LkMYUdh6mQ
He also has a video series, where he attempts to duplicate the performance of the MK262 Mod 1 military match ammo. video 6 is testing with TAC. while not the 75g hornady, it is a reasonably similar 77g OTM bullet. And a most excellent series.
https://www.youtube.com/watch?v=4iirWnaWjhc&list=PLTTrjvDib94ly8_5jqnedzK6bhXWzZyVl