When to give up on a load?

[ksubuck]

Reloading for my Browining A-bolt 25-06 with a Boss. Trying the 110gr Accubond over IMR4350.

My problem... Go to range with a clean barrel. Shoot a group of 90gr factory rounds as fouling shots. They group around 1.25 inches. Then proceed to work through 5 5-shot groups of different powder charges. Groups from 3 to 4 inches. Go home, clean barrel. Next trip to range, 5 factory fouling shots at 1.25 inches, 4 5-shot accubond groups from 2.5 to 4 inches. Take best 2.5 inch group which is a mid-range load and run a series of different seating depths. Return to range, factory fouling group 1.5 inches, 5 5-shot groups of varying seating depths 1.9 to 4 inches. Seating depth was varied from 0.010 to 0.030 off of the lands.

Is it worth pursuing the Accubond further or are these groups not worth wasting any more time and supplies? Was thinking about loading some more and tweeking the BOSS to see if I can tighten them up more.

 

[SnakeRiverEric]

Try seating further away than 0.030, all of my AB loads(7mmSTW,270,270WSM,300WSM) are seated from .050 to .125 away from the lands. Otherwise I would find another powder and start over.

 

[Tones]

The definition on insanity is doing the same thing twice and expecting a different result.... jk

I'd stop using the factory loads to foul the barrel. I have read and heard numerous reports of people running cheap ammo and fouling the bore with crappy jacketing compared to the premium bullets, causing the premiums not to shoot.

I'd be using the same projectile/loads as you are testing to foul from a squeaky clean barrel. Try that and I reckon you will see a difference.

Tones.

 

[FearNoWind]

Reloading for my Browining A-bolt 25-06 with a Boss. Trying the 110gr Accubond over IMR4350.

Then proceed to work through 5 5-shot groups of different powder charges.
Take best 2.5 inch group which is a mid-range load and run a series of different seating depths.

Seating depth was varied from 0.010 to 0.030 off of the lands.

The Browning Boss system specifications are based on factory ammunition test samples. Browning provides Boss specs. for their 25-06 in 85, 90, 100, 117, and 122 grain bullets (with specified factory ammo) and even those need to be fine tuned - as is apparent with your 1.25 inch group factory ammo. results that I'd expect to be 1/3 that size.
Based on that, your boss accessory (a barrel tuning tool) is essentially worthless when applied to reloads unless you can match the ratios of bullet weight, BC, MV, to the test data provided by Browning.
In your place, I might try .25 grain adjustments (staying within safe limits) above and below the 2.5 inch group loads with a bullet jump that provides COLB distances that correspond with the factory ammo. and see if the groups tighten up. But I wouldn't fool around with seating depths at this early stage in load development. Once I developed the tightest group possible with a given load, I'd see if setting the Boss at 4.75 for the 110 grain bullet bought you better results. Changing the Boss by a mere .25 can make a big difference.
I think the Boss system was intended for hunters who rely exclusively on commercial factory ammo. rather than the reloading hunter. For the precision reloader the Boss, IMO, only inserts another variable that has to be factored in during load development and that task requires a lot of SWAG which in turn wastes a lot of supplies.

 

[Barrelnut]

I shoot a 25-06. Just shot a couple .23 MOA groups at 100 yards with IMR4350 and 90 GN Sierrra GameKings HPBT this afternoon. Use FC brass and F210M primers. Believe me the 25-06 can shoot and a 25-06 with a Browning BOSS should shoot very well.

I also shoot 110 Accubonds with Retumbo for a hunting load and it shoot .5 MOA.

I would:

1) load the medium load from the Nosler manual for 110 AB and IMR4350. Load 21 of them at the book COL.
2) clean the rifle well.
3) shoot three of these loads for foulers. Note the group.
4) shoot three more. Note the group.
5) Now you have a baseline to work from
6) Use the remaining 5 three shot groups to tune the BOSS.
7) Now you have the best results from tuning the BOSS.
8) Now experiment with powder and seating depth if need be.

What twist is the Browning 25-06? Standard for 25-06 is 10 twist.

 

[ksubuck]

Lots of good thoughts. The BOSS does add a variable that I haven't figured out how to work around with reloading. Figured it would be my last adjustment at some point to gain that last bit of squeeze on a group. Have another rifle with one and had no trouble developing a load grouping less than MOA and then I get to tighten it up more with the BOSS. These 3 to 4 inch groups with this gun are driving me nuts.

My plan was to take this load and run 25 more at the best seating depth to date to chrono and to adjust the BOSS. Just not to sure I will get to MOA.

Whats the worst starting group sizes everyone has had that they have then been able to adjust into a respectable final grouping?

Rifle is a 10 twist

 

[AZShooter]

My hunting partner has two Browning A-bolts with the BOSS. One is a 223 which is a wonderful system for buying bulk 223 ammo and fine tuning for best groups.

The other is a 300 WSM. I made two handloads for his rifle and it was very easy. Seated bullet at longest OAL which fit and fed from the short 2.8" magazine. Worked up powder charges noting tightest group. Fine tuned BOSS. His shoots 125 nos bt and 230 br bergers into nice 1/2" groups.

I remember reading somewhere that the bedding on the BOSS system is different, spongy or soft IIRC. I would see if you can find Browning's recommended action screw torque.

I did find this thread on the A-bolt with BOSS. I linked beginning with second page.

http://www.longrangehunting.com/forums/f19/bedding-browning-bolt-boss-67007/index2.html

Anothter thread regarding torque of the action screws: One poster mentions calling Browning and their comments:

"When I called I spoke to their tech support about torque specs and he told me that the torque varies from rifle to rifle usually in the 35-45 in-lb range, and upwards of 65 in-lbs, but are usually in the 35-45 range he also said you would have to play with it, go out there and shoot and see which is best for the rifle by changing torque settings."

http://forum.snipershide.com/sniper-hide-gunsmithing/33643-browning-bolt-hunting-rifle-problems.html

I looked around and found another article where several posters said they had action screws that tended to loosen up and to check them frequently.


http://www.reloadersnest.com/forum/topic.asp?TOPIC_ID=17344

 

[Truc]

my first thought is you're shooting a sporter rifle, why are you shooting 5 shot groups? hell I don't tune a competition rifle that way. 3 shots will tell you everything you need to know if the load will shoot. Load 3 each at 3-4 grains of powder say 52-55 gr. Find which shoots the best, then adjust seating depth, then adjust powder 1/2 gr increments either way then adjust seating depth. 2-3 thousands.
There is a well known fact, 3 shots test the gun or load and 5 shots test the shooter.

 

[ksubuck]

my first thought is you're shooting a sporter rifle, why are you shooting 5 shot groups?

There is a well known fact, 3 shots test the gun or load and 5 shots test the shooter.

Probably true. Figure this topic has been argued many times. Maybe I'm not a great shooter and an unnoticed flier or three might hide a good group. I really debated about 3 vs 5. Figured 5 would be a good challenge until I proved to myself that I was up to snuff at the bench. I'm new to reloading for accuracy. Used to load for volume, speed, and short range hunting.

 

[ksubuck]

I would:

1) load the medium load from the Nosler manual for 110 AB and IMR4350. Load 21 of them at the book COL.
2) clean the rifle well.
3) shoot three of these loads for foulers. Note the group.
4) shoot three more. Note the group.
5) Now you have a baseline to work from
6) Use the remaining 5 three shot groups to tune the BOSS.
7) Now you have the best results from tuning the BOSS.
8) Now experiment with powder and seating depth if need be.

This is pretty much my plan now. Loaded them up tonight. Thinking some magnetospeed chrono work while fouling. Went through the rifle and checked torque, still running at manufacture suggestion. Don't think a problem cause will group manufactured rounds. BOSS was at 4.5, will work up from there.

 

[FearNoWind]

...
In your place, I might try .25 grain adjustments (staying within safe limits) above and below the 2.5 inch group loads with a bullet jump that provides COLB ... that correspond with the factory ammo. and see if the groups tighten up.....

Forgive please the error. How I got COLB in there when it should have been "CBTO" is a mystery but I suspect you figured out what was intended.

 

[ksubuck]

Broke through MOA this morning with adjustment of the BOSS. Best group 0.986. Still have some work to do. Maybe I will do some more seating depth adjustment in the future.

Chrono work not too pretty, 2850fps with an embarrassing SD and ES. Suppose the Nosler max load isn't showing any pressure signs so maybe I will work up a bit and see if there is another node close.