Please analyze my ladder test

[ATH]

Hey guys,
I did a ladder test today on my Sendero...I think it turned out pretty well, for some reason I shoot a lot better off a bipod than the bench.
I'm no expert but I think I have this one read correctly, but I'd like to see what the experts have to say before I proceed /ubbthreads/images/graemlins/laugh.gif

Relevant parameters:
Remington Sendero 300WM
300 yds, wind 10-15 mph gusty mostly from behind; component pushing right for shots 7-12 more than others
200gr Accubond, Re22 powder, Fed215 primers
*Since the gun seemed incredibly fouled on 14 shots and possibly losing accuracy on my last shoot, I ran a patch before every shot just to keep things consistent if nothing else until I get a good load to test the accuracy/fouling issue.
Shots/charge:
S - sighter (68.6gr), adjusted aim after
1 - 68.6
2 - 68.9
3 - 69.2
4 - 69.5
5 - 69.8
6 - 70.2
7 - 70.5
8 - 70.8
9 - 71.1
10- 71.4
11- 71.7
12- 72.0
13- 72.3
14- 72.6
15- 72.9
16- 73.2
17- 73.5

[image]http://www.hunt101.com/showphoto.php?photo=401695[/image]

Hope this comes through sized ok...

Side question...My book says 73.5gr is max charge, yet so far zero signs of pressure and bolt lift like factory ammo. Stop here or test a little higher? No chrono today unfortunately.

 

[ATH]

Trying one more time to do this cleanly...

 

[royinidaho]

I'd say consider scoping in on 14 through 17.

I'd also continue up in powder (carefully) until pressure signs occured to some degree.

Also, is the target placed firmly against a backer such as cardboard? If the backer is good the holes are crisp. Several of the holes appeared to be "out of round" but it was hard to tell with the amount of tearing around the hole.

 

[ATH]

It was on plywood, and probably not held all that firmly since the pins wouldn't go in to the heads. The 100yd targets I shot a couple days ago with similar loads had crips holes so I'm not concerned...

 

[sewwhat89]

I second 14-17. I know you have to take advantage of the time when you can shoot, but I would be 'nicer' to have the ladder shot in calm conditions.

That being said, I went to 78 gr RL 22 with 190s before I hit pressure. Keep going up with caution.

 

[Jimm]

ATH ,

You are probably very close to the "last " shot in the accuracy node displayed in shots 14-17. 73.8 and possibly 74 will go in that same node .

What I have seen in 300wm with RE22 and 190-200 gr. pills is that the last accuracy node before overpressure will come around 73.5 grs as a median charge wt.
The next node above that will almostly surely flirt with pressure probs.

In a 28" Broughton 5c bbl velocities with that combo ( 73.5 RE 22 and 190-200 pills ) are around 3050 avg.

Jim B.

The

 

[abinok]

NO velocities? bummer dude!
300yds?
as has been suggested, 14-17 is where to start looking. 4 consecutive rounds piled into less than 1/3 moa... definately.
Being a conservative guy, id hold off on pressing beyond book max by too much untill I had a chrony in front of the muzzle. If you don't have one avalable, email me, mine travels my mail occasionally when its time for vacation, and theres not any new loads to chrony.

 

[ATH]

Thanks everyone, and abinok for the chrony offer. I DEFINITELY wouldn't go over book max without one! I'll either borrow a buddy's or I'm going to bid on a used one today and see if I get it.

I thought 14-17 as well, this one was pretty clear-cut...what an ammo saving tool! I'll probably load 4 at the charges for 15-17 and also bump up to 74gr and try that...and stop there no matter what.

Yes, I thought those last shots were grouped pretty well for a totally factory gun and someone who probably shoots less well with a scope than most of you do /ubbthreads/images/graemlins/laugh.gif

 

[G. Brice Martin]

Newby here, please go easy. This (ladder) test is new to me. You shoot all incremental loaads into one target and look for the sweet spot, or "group"? I've tested incremental loads of , say, 3 rounds each and looked for the broad increments that group well. This looks like a fine shortcut to the same goal. Do I have it?
Thanks

 

[ATH]

I'm not the most experienced myself, but....

The test shows the nodes in the harmonics where the gun shoots well. Theoretically, a .3 grain change should not move the shot very much at 300 yds. Yet on the target you see many of them shifted impact by several inches. This must be due to some other influence than just the charge (barrel harmonics etc).

In a couple spots, namely shots 13-17 on my target, the shots do group very close together, indicating a node where the shots behave as they should. My understanding is that on these nodes, the gun will also be more accurate than at any charge outside of a node as the harmonics are good.

I'm actually going to shoot the groups to verify the results of the ladder test within the next couple days and I will post results when I have them.

 

[G. Brice Martin]

I do believe I understand. This is based on barrel vibration and the resulting shot dispersion, same being least when the muzzle is at the null point. (Much of what I know I learned from Harold Vaughn (RIP) in "Rifle Accuracy Facts".) What a great tool!