I am going to venture into some subsonic loads for shits and giggles. Came across some stuff that I saw different opinions on.
Do you need to open up the flash hole or is this more of a theory that doesn't really do much? if it does do something significant, what happens if it got mixed up with a full powder charge load?
Magnum primer vs Standard Primer?
Flat base round nose bullets seem to be what works best and for the life of me I cant figure out why. Will the BTHP's work just as well?
Im going to try out the 143 ELD-X to see what happens in my 260 rem.
Having been into subs for 25 years now I'll tell you what I know as fact for my .300wm/.308/.223
I do not use jacketed bullets at all, there is too much variance in the bearing surface's which effects SD/ES.
Subs are harder to load for small groups at long than H/S projo's
Bullet nose design vs twist rate has to be watched, bullet weight means nothing except on target performance.
Primer pockets do not need to be opened, nor the use of mag primers.
Fast burning pistol powder is more finicky with jacketed bullets vs cast. 700X is the most consistent for me with Clays second, but I have to weigh both as my thrower jams up with them. Red Dot is my std playing load, but when it has to be in the eye 700X gets used, but those have to be weighed.
BTHP's will work but only in faster than normal twist rates for the cal. I run a semi pointed to 600 yds leaving the muzzle at 1080fps an they get there point on, in less than 1-2.5moa groups if you can read mother, an depending powder used.
I do not use a dedicated smoke pole for subs, I have subs for everything. The 300wm an .308 leave the muzzle at the same speed so there is no different up numbers to remember past the difference between H/S an a sub in the same weapon. In my .308's there is 13-15moa (depending temp)of up needed to be POA/POI over my H/S zero(same weapon) an 1.5 moa of left wind for S/D. In my 300wm it's 14-16 (depending temp) an 1.5 left wind for S/D. The S/D(any weapon) stays the same until about 250-275 yds then I have to start adding more left wind as I shoot longer. Different cast bullets will drift different in all my sticks. There is very little difference in up past 100yds in my 300wm vs .308 as the bullet is the same, but the mechanical off set is different.
Remember it's not what you hit them with it's where you hit them at. Knowing the targets anatomy/weakness is king on live targets with subs.
I bought into all the internet hype about sub ammo for a long time, until nothing was working like I thought it should. So I went rouge an the trial started. We now have sub only shoots, an have learned much about what works an what is pure internet B/S. Get you ammo down, then start learning to read mother nature ( temp/wind/%h20). I shoot 10-20X as many subs as H/S now, an deer sized targets are give me, much like a shotgun to rabbits, using them.
I run a Lyman semi pointed cast bullet(311332BV) using wheel weighs an a gas check. The total weight is 193 grs (lube & gas check) Using the gas check there is no leading, an the first shot or the 100th is in the same place even when switching between H/S an subs.
Hornady is the only gas check I use as most all the others are designed to leave the bullet at the muzzle, bad news for a can. The Hornady has a locking ring that grips the bullet, an when on correctly will not come off even when impacting steel.
Some say a .223 sub is worthless an mostly are past 250 yds but, they will kill deer to 100yds as well, however shot placement is key.