6br light weight bullets test target,... question

[Lefty Trigger]

Working on loads for my new 12 twist 0 freebore 6br. Trying bullets in the 55gr to 68gr range and worked up a load with impressive results (for me) using IMR8208XBR powder. Started at 32.0gr and worked up to 32.9gr just 1 tenth under max with Sierras data with their 60gr Varminter bullet. 32.0 and 32.3 gave the best groups but the ES/SD numbers were not that great and got better as the load went up but the groups got worse. I have already done a seating depth test and .015-.018 shot the tightest groups. I'm thinking primers next at the 32.0gr load just to see if I can improve the numbers. I'm not going to get too hung up on these numbers because my max distance is 300 yards but groups size is king.
I have most primers but powders are very limited that's why this test is H4985 and IMR8208XBR are used. This target was shot at 200 yards and Federal 205 standard was the primer used and Norma brass. Take a look and tell me if I'm missing anything with this target.

 

[LHSmith]

I have shot SR BR since 2003. I rarely chronograph PPC and BR loads. Ditto my mentors. I remember when the SR russian primers became available they were getting ridiculously low ES/SD numbers, yet they did not use them for very long nor did SR Russian primers win favor of the top shooters of the time.
I was taught to look for the smallest bullet holes as this is the load was the most stable, i.e. "in tune" = least affected by wind. And of course any load development target is inconclusive without the use of wind flags.

 

[Bill Norris]

Sometimes the CCI 450M primer worked better for me with that 60 gr. Sierra bullet and H-4895 but I was shooting 1-14 Twist.

 

[JEFFPPC]

Where did you start with your seating depth test? All those 2 and 1s tell me your not there or close.

 

[Lefty Trigger]

Where did you start with your seating depth test? All those 2 and 1s tell me your not there or close.

Started at lands and went out to .040 jump. Pushing at the lands would spike the pressure with the 8208XBR, they just seemed to like a little jump. I did not account for the strays because it was windy when shooting and I have no flags or know how to read them if I did. The target holders were swaying back and forth and would have to wait till they settled down to take a shot. That's why I said they was good "for me" as always I'm open for suggestions, I could back the load down and retest seating depth?

 

[BoydAllen]

IMO testing at 200 in that much wind, with light bullets and no flags is a waste of components.

 

[LHSmith]

Started at lands and went out to .040 jump. Pushing at the lands would spike the pressure with the 8208XBR, they just seemed to like a little jump. I did not account for the strays because it was windy when shooting and I have no flags or know how to read them if I did. The target holders were swaying back and forth and would have to wait till they settled down to take a shot. That's why I said they was good "for me" as always I'm open for suggestions, I could back the load down and retest seating depth?

Seriously, without flags it's a crapshoot. Just put simple survey ribbon on poles, sticks at 50 yard intervals and shoot only when the they indicate the same wind pattern- direction and velocity ( are they limp or blowing horizontal? ). If you happen to shoot when the tails changed (it will happen a lot) - make a note on the target and you will soon begin to reconcile why shots go elsewhere from the POA.
You also must be diligent about removing all parallax from the scope at that specific range (distance) and do it every shoot session as atmospheric changes will affect the setting.
Next you have to learn to watch for mirage by closely observing if the POA meanders around the target without any influence on your part. Most know not to shoot in a boiling mirage, but a slow mirage will change your group considerably.

 

[Flyshooter]

Lefty Trigger,
If you can find some RL-7 or AA2230 along with 55 grain Sierra blitzkings or 58 grain Vmax then try those combinations.....and use 450 CCI magnums with Lapua cases, as you can run some stout loads with no issues.

I’ve chambered so many 12-14 twist 6BR zero freebore barrels that nothing else is usually attempted as those two propellants and bullets have never failed to drill little tiny groups.......group after group after group.

The Sierra 60 HP shoot well too.....but my rifles are for prairie dogs and the blitzkings or Vmax simply evaporate PD’s into an instant slurry.

Additionally all my PD rifles are braked, makes seeing the carnage or occasional miss easy to spot.

Nevertheless 6BR zero freebore’s are a rifle every shooter should have in my humble opinion. Easy to obtain 3700+ FPS speed......fun, effective and accurate.

 

[JEFFPPC]

Started at lands and went out to .040 jump. Pushing at the lands would spike the pressure with the 8208XBR, they just seemed to like a little jump. I did not account for the strays because it was windy when shooting and I have no flags or know how to read them if I did. The target holders were swaying back and forth and would have to wait till they settled down to take a shot. That's why I said they was good "for me" as always I'm open for suggestions, I could back the load down and retest seating depth?

Trying to develop a load in bad conditions is a waste of time, components, and barrel. Flags can be simply flagging tape hung out. Your short changing yourself not getting into the lands as a testing option. If your load is to hot drop it a bit. If you want good results it takes thought out preparation. Sloppy preparation will not bring good results. Slow down, prepare properly and you will be rewarded. If not you will get what you have.

 

[xswanted]

Might want to try the 80 or 88 Berger.
I’m not sure how they work with zero free ore but they shout very well with my 12 twist.

 

[Lefty Trigger]

IMO testing at 200 in that much wind, with light bullets and no flags is a waste of components.

I agree but I have to work with what I have and when I can. Our range is kinda down in a bowl so the winds come at all directions at various places down range. Not ideal but pickings are slim in Ohio...

 

[Lefty Trigger]

Lefty Trigger,
If you can find some RL-7 or AA2230 along with 55 grain Sierra blitzkings or 58 grain Vmax then try those combinations.....and use 450 CCI magnums with Lapua cases, as you can run some stout loads with no issues.

I’ve chambered so many 12-14 twist 6BR zero freebore barrels that nothing else is usually attempted as those two propellants and bullets have never failed to drill little tiny groups.......group after group after group.

The Sierra 60 HP shoot well too.....but my rifles are for prairie dogs and the blitzkings or Vmax simply evaporate PD’s into an instant slurry.

Additionally all my PD rifles are braked, makes seeing the carnage or occasional miss easy to spot.

Nevertheless 6BR zero freebore’s are a rifle every shooter should have in my humble opinion. Easy to obtain 3700+ FPS speed......fun, effective and accurate.

I do have a pound of RL7 and some Nosler 55gr ballistic tips but even with a 0 freebore there is very little of those bullets in the case. Any starting points for the RL7?

 

[Flyshooter]

Lefty Trigger,
Say with a zero freebore your bullet should be at least 1/2 to 1/3 way down the neck while touching the lands.....This of course depends on your bore diameter, still you should be a solid 1/3rd the way in the neck and have land contact.

I don’t shoot the 6MM nosler 55 ballistic tips as every time I’ve tried them, and it was a lot as I so wanted them to shoot.......either the 58 Vmax or 55 Sierra Blitzking shot much tighter.

Otherwise 29.5 - 31 grains of RL-7 with a 55 or 58 grain bullet.....BUT you need to use a thick cup primer and Lapua cases......still you rig might shoot those 55NBT just fine. None our group of 6BR zero freebore dog shooters shoot the noslers (5 of us) doesn’t mean your won’t......try it.

 

[Murray Brook]

My 6mmBr shoots great with the 64 Berger Column and AR-Comp. CCI-450 primers and .010 in the lands. Might want to source this powder if you can to give it a try in your 6BR.

 

[JFrank]

What's wrong with 32.1 then double check your seating ?

 

[Dusty Stevens]

Got a few suggestions- first the 12tw needs a longer bullet like an 80gr. Next, back your powder off and go to a hard seat jam. If you get to a zero on touch youre about .015 too short. Like was said get them flags out and i suggest going to 100yd to eliminate some variables. Youve got way too many obstacles here to overcome. Put the chronograph up until you get your load then see what speed it is and keep it there.

 

[jackieschmidt]

IMO testing at 200 in that much wind, with light bullets and no flags is a waste of components.

^^^^^^^

 

[Lefty Trigger]

What's wrong with 32.1 then double check your seating ?

Thats next,... loaded up some at 32.0, 32.1, 32.2 for testing. Set aside the primer test and going to run seating again from .010 off into hard jam with a slightly less load.

 

[Lefty Trigger]

Got a few suggestions- first the 12tw needs a longer bullet like an 80gr. Next, back your powder off and go to a hard seat jam. If you get to a zero on touch youre about .015 too short. Like was said get them flags out and i suggest going to 100yd to eliminate some variables. Youve got way too many obstacles here to overcome. Put the chronograph up until you get your load then see what speed it is and keep it there.

With the 0 freebore there is a lot of bullet back in the case with the longer bullets. I have 75gr V-max, Berger 80gr flat base target and 88gr flat base target on hand but in limited amounts.
Getting to shoot on the 100 yard range is a total crap shoot. Might be busy all day? There is never a sole on the 200 yard range thats why I use it all the time. Our range only has 4 lanes at 100 yards but the 200 is a completely different range with 10 lanes. Since all the crazy people are over there with everything from pistols to 338 magnums its safer on the 200. I even asked about moving closer or setting targets closer and the club thought that was a bad idea as it would give other shooters ideas. Its hard to learn in less than optimum conditions.

 

[boltfluter]

Lefty,

I too would do your load work at 100 yds early in the day if possible. Without any kind of flags, 100 yds is tough, but 200 yds can be a real nightmare! Been there and done that! Good luck! I would take my own target and set it at 100 yds as long as it is safe to do so.

Paul