Custom rifle

[FEENIX]

The "NUT" behind the trigger should set their limitations and their equipment's capability, not by others.

I have full custom/semi-custom rifles that are shooters, but this budget factory rifle (TC Arms Compass in 6.5 CM) shoots a nice group at 200Y with the cheapest factory ammo (Deer season XP 125g) I can find at the time for barrel break-in.

Its first harvest was a 200Y heart shot at a WT doe.

 

[Dragoon300]

I recommend using Applied Ballistics software and their custom drag curves, instead of G1 bc (think 45 ACP projectile) or even G7 (boat tail) which is better to use for most rifle bullets.
And, don't forget the wind at range. Wind is the biggest problem at long distances!

 

[cjuve]

BC's actually aren't constant they degrade throughout the flight of the bullet as velocity drops.

What we see as advertised BC's are at best averages.

I'm still trying to wrap my head around that one as well hoping for more of an explanation.

The only way I can see groups getting dramatically worse would be if the bullet was only marginally stable to start with providing the shooter has everything right on their end and the wind is not gusting.

All of these groups were shot during load development not final loads.

Looking at the POI from surrounding charge weights I have come to the conclusion that what you are seeing is a result of bad harmonic timing. If you look at the targets at 600 yds (orange dot is about 2") you will see that the 95 grain load strung vertical to over 5" and had an overall higher POI than that of the faster 95.3 grain load which had zero vertical dispersion. The lower charge load was exiting the muzzle just after the barrel had started its upward movement from being stationary at the bottom of its harmonic cycle. The higher charge load exited the muzzle at the bottom of the harmonic cycle while it was at its most stationary point. When you get on the wrong side of this cycle interesting things happen which don't always show up at close range.

The timing of the barrel cycle is really evident when you shoot long range ladders, it is part of the reason that you can have a series of loads that impact within the same vertical even when they differ in charge weight by up to 1.5 grains. I have found that a properly tuned load can hold the same POI even when shooting .5 gr or more difference in charge weights. This is also why you can a load with higher than normal es/sd still print good groups at long range.

 

[Joefrazell]

The "NUT" behind the trigger should set their limitations and their equipment's capability, not by others.

Probably the best spoken words in this entire thread yet.

 

[Joefrazell]

BC's actually aren't constant they degrade throughout the flight of the bullet as velocity drops.

What we see as advertised BC's are at best averages.

I'm still trying to wrap my head around that one as well hoping for more of an explanation.

The only way I can see groups getting dramatically worse would be if the bullet was only marginally stable to start with providing the shooter has everything right on their end and the wind is not gusting.

Yeah or a parallax issue

 

[Gene Allen]

What in all the experienced shooters opinion is a good ES/SD for non magnum and magnum loads, I know single digits would always be best but what would be acceptable, I can get 6.5 creedmoor in single digits but it is harder in the magnums for me?

 

[WildRose]

What in all the experienced shooters opinion is a good ES/SD for non magnum and magnum loads, I know single digits would always be best but what would be acceptable, I can get 6.5 creedmoor in single digits but it is harder in the magnums for me?

If you can get it down under 25fps you should see very little spread or variation in your groups. Single digits are great but don't pull your hair out trying to get there.

The big issue is that once you get beyond 400yds even a change of 50 FPS from shot to shot can seriously impact your accuracy while a change of 15-25fps is going to have very little impact on your POI.

 

[Gene Allen]

Thanks for the info i usually get my 3 magnums into the mid to low teens, so I won't worry about it sounds like that should be ok !

 

[JTComfort]

Thanks for the info i usually get my 3 magnums into the mid to low teens, so I won't worry about it sounds like that should be ok !

"Should be okay…". You should be okay out a good ways.

 

[WildRose]

The "NUT" behind the trigger should set their limitations and their equipment's capability, not by others.

I have full custom/semi-custom rifles that are shooters, but this budget factory rifle (TC Arms Compass in 6.5 CM) shoots a nice group at 200Y with the cheapest factory ammo (Deer season XP 125g) I can find at the time for barrel break-in.

View attachment 336776
View attachment 336774

Its first harvest was a 200Y heart shot at a WT doe.

Sometimes you just find a real winner.

I'm looking at a couple of JP Sauers right now and having a hard time talking myself out of them.

 

[FEENIX]

Sometimes you just find a real winner.

I'm looking at a couple of JP Sauers right now and having a hard time talking myself out of them.

Agreed! Sauer makes beautiful rifles.

 

[Joefrazell]

What in all the experienced shooters opinion is a good ES/SD for non magnum and magnum loads, I know single digits would always be best but what would be acceptable, I can get 6.5 creedmoor in single digits but it is harder in the magnums for me?

You can run it through a ballistic calculator and see what variations will cause what kinda vertical and distance. Wildrose is right and 25 fps is just fine generally speaking. Elr guys wants low es more so then most.