Subsonic long range big learning curve

[Blancoalex]

So far going down my Subsonic long range learning curve , here are some things that worked so far for me.

I have gotten to be proficient to 200yds so far.

Use quality brass, neck turn if needed for consistent neck tension
Short FB stubby bullet works best, use highest BC you can get being a stubby FB bullet
My best groups at 100yds came with 3.0 SG stability #
I chamferd the inside primer flashhole pretty good to help primer flame, did not open primer hole.
Weigh powder using most accurate scale you got, try to be exact on your charge.
I took .001 off my resizing die button to create a tighter grip on bullet to "hold it a little longer" for better powder burn.
Scope with lots adjustment needed, rough guideline is 5 mils per 100yds.

I had been using some TulaMag primers but with start experiment using different primers to see if can get even less ES.

Rifle steering/control very important.

300-400yds is new goal, as still have 10 mils left on my scope to use.

Pretty fun to hear PUFF and hit your target.

 

[Bucklowery]

I hope to start working on my loads again next week I am still not accurate at 100. I get one flyer usually the first one. I got my crimp die today. We will see

Thanks

Buck

 

[Blancoalex]

Reading about using madrels for opening case mouth after sizing lead me to taking off .001 off sizing button. You can feel the extra grip it has on bullet. Should be similar to crimping. I just like having extra grip on whole bullet in neck.

Also now on search for short flat base high BC bullets. Kinda oxymoron, like saying Subsonic Long Range.

 

[Bucklowery]

I am shooting the outlaw Bullets but they are not short. Flat base, yes but 200 gr and for hunting. They stabilize great to 100 in my savage 26" bbl. I have not shot further yet.

Thanks

Buck

 

[Dean2]

If you are going to do a lot of longer range subsonic shooting, get a fast twist barrel so you can use heavy for calibre flat base, spire point bullets, which tend to be quite long. Also, put a light crimp on the bullet. Up to 1000 fps Trail boss is still really quiet, even at 1,100 it is pretty good. Both of these will up you accuracy big time and allow you to shoot to 300 yards pretty consistently.

 

[Blancoalex]

Right now I am using 6mm- 7 twist and Nosler 55 gr fb Varrgedon. I did try some older Rem 100 PSP bullets yesterday by they only got 2-3" groups at 100yds. Starting with 6mm to learn as have plenty components, except now finding best high BC bullet that will safely work in my Thunberbeast Ultra 9 can.

 

[QuietTexan]

Also now on search for short flat base high BC bullets. Kinda oxymoron, like saying Subsonic Long Range.

Berger makes the "6BR Column" 64gn FB bullet - .810" long, BC of .231. Specs for a 14 twist so you should be good, Berger calc says CG = 2.91 at 1080 fps.

6 mm BR COLUMN Target Rifle Bullet

Flat Base Column Target Bullets are often used out to mid-range distances of 300 yards or more where a boat tail is not applicable. Highly accurate, the Flat Base Column Target uses J4 Precision bullet jackets for construction.

bergerbullets.com

The Berger 88gn FB "High BC" varmint bullet has great BC but is over an inch long. They also make an 80gn FB.

Sierra 85gn SPT is flat based, BC .304 under 2200 fps. Looks similar to the Nosler 70gn Varmageddon on paper.

 

[Dean2]

We can't use suppressors here in Canada. All of our quiet loads have to be accomplished using powder, speed and bullets only. It is easier to make larger bore rounds that are quiet. The smaller the bore the harder it is, but I do have some really quiet 22 Hornet rounds made with Trail Boss that work well to 100 yards for shooting pests around developed areas.

 

[Mr. Magoo]

I know this is an older thread but im trying to find out why flat base bullets are perferred? It sounds counter intuitive to getting longest range/ best trajectory from 1000fps. Seems you would want to use the highest bc bullet for the caliber you can get?

 

[Bucklowery]

It has to do with the boat tail moving at slower speeds not bc
Thanks

Buck

 

[Mr. Magoo]

It has to do with the boat tail moving at slower speeds not bc
Thanks

Buck

You mean like tail wagging?

 

[Dean2]

I know this is an older thread but im trying to find out why flat base bullets are perferred? It sounds counter intuitive to getting longest range/ best trajectory from 1000fps. Seems you would want to use the highest bc bullet for the caliber you can get?

Fired at 1000 FPS, within reason the difference in BC between boattail and flat base won't make a difference. Your effective range is only 250 yards so when they talk about longrange Sub sonic loads it is entirely different than the LR we usually discuss.

Generally, heavy for caliber make far better performing subsonic loads than light bullets so you do gain BC and SD that way. It isn't like a 1000 FPS round ball, the Spitzer bullets don't shed velocity like a ball or 50 cal Mini Ball.

The flat base gets more push from the gas, seals the bore better and is generally easier to stabilize at slower speeds as they tend to be shorter. Hope this helps.

 

[QuietTexan]

You mean like tail wagging?

It's an argument of accuracy vs precision. Flat base bullets (at least in the past) resulted in more precise groups that won absolute-group-size races. I'm talking sub-0.100" groups here, so the ragged bleeding edge of absolute precision.

It used to be about inconsistency in the swaging of the bullet when it was formed. For short-range benchrest the variance in BC (describing the physical shape variances) between individual bullets was much more important than the actual BC itself, and boattail designs had a higher variance more because of the additional work done to the bullet jacket to form the boattail. It's becoming less and less relevant IMO because factories are churning out significantly more-consistent bullets now at higher volumes than ever before.

But when shooting for X-rings then accuracy becomes the overriding issue, and placing bullets where they need to go is paramount so higher BC benefits more against the wind. There's no reward for smaller group size past a certain point (the size of the X-ring), so instead of continuing to optimize BC variance past the point once groups got small enough to all fit in the x-ring, focus could shift to improving overall BC and keeping the group centered on the x-ring in a wider range of conditions.

 

[Mr. Magoo]

Thanks for the replies, makes sense what youre saying.

I dont plan on shooting to 1000y for subsonic stuff but I can easily ring 8" plates regularly 200 with my 22 so it didn't seem too far fetched to push that out further with something optimised for longer ranges.

I don't have a need to hunt deer with subsonic stuff- just small game, hogs, defense, and just fun.