So what would you do? FTR load advice

[jlow]

The question is say you are working up a load for FTR and the bullet is a 185 Jugg, you are going to do an OCW.

Tested single charge weight up the scale and they all shoot pretty much the same POI and no pressure sign. The bullet is seated around 10 thousands off and you use the MVs you’ve collected and QL to figure out where accuracy node is.

You shoot an abbreviated OCW with a range of 1.4 grains at 0.3 grain spread. So everything is still shooting at around 0.5 MOA or less (3 or 5 round groups). You check the average POI and you see it’s not moving between 45.5 to 45.9 grains (and only very slightly at the other charge weights). All three of the above charge weight 45.5, 45.8, 45.9 grains is around 0.4 MOA and single digit SD.

Would you shoot a 5 round group at 45.8 to confirm and call it a day or would you bother to try to adjust seating depths to try to get a tighter group?

 

[mac86951]

What distance is the ice target at?

Darn spell correct... OCW not ice

 

[jlow]

Not sure what you mean by ice target, but the OCW was of course run at 100 yards. FTR will be between 600 yards to 1k.

 

[mac86951]

Not sure what you mean by ice target, but the OCW was of course run at 100 yards. FTR will be between 600 yards to 1k.

Lol! Darn autocorrect.

Move over to 300+ yards to see poi impact. Heck; 1000y would be best, but more dramatic.

 

[jlow]

Lol! Darn autocorrect.

Move over to 300+ yards to see poi impact. Heck; 1000y would be best, but more dramatic.

Checking out the load at extended distance is what I will do regardless. The question though is would you do the seating depth study before?

 

[savageshooter86]

I'd test seating depth. That bullet should shoot better than that. I expect a lot out of my guns though. High two's, low threes. Max group accepted at 100.

 

[mac86951]

Checking out the load at extended distance is what I will do regardless. The question though is would you do the seating depth study before?

Seating depth, or charge volume I find produces far better results at distance. Testing poi to aim; or group size at 100y provides some information; but it's easier for a flier to have you looking elsewhere. Looking at vertical dispersion in an effort to categorize the range that produces the minimal acceptable vertical dispersion needs some distance to create meaningful separation of in range and out of range values.

 

[savageshooter86]

Seating depth, or charge volume I find produces far better results at distance. Testing poi to aim; or group size at 100y provides some information; but it's easier for a flier to have you looking elsewhere. Looking at vertical dispersion in an effort to categorize the range that produces the minimal acceptable vertical dispersion needs some distance to create meaningful separation of in range and out of range values.

Yes. I do next test at 500 yards. 100 to verify I have load narrowed down. 500 to fine tune and verify

 

[jlow]

So you guys would not bother to try to tighten groups up using seating depth at 100 yards?

 

[Comrade Terry]

So you guys would not bother to try to tighten groups up using seating depth at 100 yards?

I go to 300 for that. 100 doesn't tell me too much of anything.

 

[jlow]

I go to 300 for that. 100 doesn't tell me too much of anything.

I will not get pulled into THAT debate....

 

[Ned Ludd]

What powder, barrel length, and velocity range are you seeing? Of course it all depends on the powder, but that's a pretty hefty charge weight with the 185s if you're using Varget or H4895, even for a long freebore chamber. Again, it can totally depend on the load specifics, but in my hands the Jugs always seem to tune in at about .015" off the lands, then stay tuned out to at least .025" off; they probably would have stayed in tune even farther off the lands, but I haven't normally tested them any farther (no reason to).

If you're certain your charge weight is where you want it to be, I would absolutely do a rigorous seating depth test. I typically test from about .006" off to .024" off in .003" increments, perhaps a little farther off if I'm feeling motivated, all shot at 100 yd. Most of my loads seem to tune in nicely between about .015" and .020" off the lands. At 100 yds, we're talking about going from perhaps half or 4 tenths of a minute, down to the 0.3s, or even 0.2s for 5-shot groups, if I'm really on the ball that day. In any event, if it's going to tune in any better, it should be obvious, even at only 100 yd. I hope to see at least two to three .003" increments in a row with similar minimal grouping, then I load to the longest of those, which gives you a slightly longer window before having to deal with land erosion.

After the seating depth optimization, then you'll want to validate the load at longer range.

 

[RonAKA]

The question is say you are working up a load for FTR and the bullet is a 185 Jugg, you are going to do an OCW.

Back up to 300 yards to do your test so you can see how elevation of POI changes with velocity. Shoot a number of shots at different load over the prospective loading range. You can shoot more than one shot at the same load. Just be sure to record point of impact of each individual bullet and each individual velocity. Yes you will need a good spotting scope (or come in to 200 yards).

Use Excel to plot just the vertical point of impact vs velocity. Us the scatter graphing type and insert a trend line. You are look for a velocity range where velocity is going up but point of impact is not going up, or even dips some. That is your sweet spot. See this graph in the 3400-3420 range, as an example .

Once you have established the sweet spot velocity, then try changing jump from 20-25 though to 10 thou jam to see which jump or jam gives the best groups. That is unless it is a VLD, and in that case Berger says it is worth trying big jumps up to 0.120" or so.

 

[savageshooter86]

Do it at 100 yards first. That'said my input. Get an idea of what load and different seating does. But once you get an idea node, don't keep testing and retesting at 100. Because it will just be repeating and just practice. I do 100 yards first then next distance is 500. Then straight to match for final testing

I'm no expert, but my results are consistent so far for me in my testing and match results at 600 yards and 1000 yards.

 

[jlow]

Gstaylorg – this is that Bartlein 30” that I was talking to you about. Freebore as it turns out is .170” (sorry initial confusion on my part). MV at 45.8 grains of Varget was 2,784 fps. MV was still linear up to 46.3 grains (2,815 fps) which is as far as I went.

What you said about “being on the ball” is my only hesitation of tying to shrink the group. I am using a NF Competition but frankly not sure of my ability to consistently shoot in the twos… Just being honest....

RonAKA – appreciate your input but I am pretty much sold on OCW and an additional ladder is not in my horizon.

 

[mac86951]

Glad to see all of this good advise.

Not much I can add, other than my reasoning behind my madness.
To summarize, I've had great luck in short range groups by testing at 300 for charge weights and seating depth to get a ball-park range of values for nodes; then bring it in to 100 and group test in multiple groups of 5 or 10 to check consistency. Smallest agg wins my pick.

F-class loading; I rough in my nodes at 300; then load up samples for multiple events and let scores and notes do my deciding. I make sure to do local event in summer and winter to get temperature in my evaluation.

One takes more shots; one takes more time. Time always gets me better info; I'll have a load for summer and winter, or best for all conditions to allow more practice time.

300ish is a number picked outta my hat; far enough to see velocity changes is the goal. My 222 shows good dispersion at 200y; my 7saum needs 500+.

-Mac

 

[Elwood]

I'm with Gstaylorg, seating depth accuracy windows can be very small or very large, just like they are with powder. Your 10 thou could be at the start or the middle or worst case at the end of the seating depth window.

I think it was Erik Cortina's accuracy at 100 yards thread that got me into working back seating depths in .3 thou increments, until then I had largely scoffed at the idea and usually worked back in .5 thou or greater! I certainly had my eyes opened with two rifles I tested.

 

[Down South]

What i personally do is a node test at 100 or 200 if its calm wind wise and use a seating depth that i know will usually be in the ball park (.010 to .020 jump). Once i see the node and know roughly where i'll end up i take it to 300 yards and fine tune my powder charge in .1 grain increments. Once i have the powder charge nailed down i fine tune the seating depth in .003 increments. I do all this at 300 yards (early morning or late evening in calm conditions on a concrete bench and front rest). I use a Oehler 35P chrono while testing loads also. Every load i've worked up like this has shot very well at 1000 yards.

 

[Mozella]

So you guys would not bother to try to tighten groups up using seating depth at 100 yards?

Unless you are putting all shots in a 5-shot group in the exact same hole, you can learn everything you need to know at 100 yards. It's just that the measurements need to be more precise; you can't use a carpenters tape. If you can get to a nearby 100 yard range early in the morning and test in zero wind conditions, you will be way ahead of someone driving long distances to get to a 300 or 600 yard range.

Get "On Target" software and use it to accurately measure the bullet holes in your scanned or photographed targets. Plus use the software to save, catalog, and study your range results. If you're looking for tiny changes in performance, you gotta' measure in small increments. And, more importantly, you need to do everything you can to eliminate the HUGE effect wind can have on your POI. Masking a small difference in POI with a large wind shift makes for bad data gathering.

And please don't anyone try to tell me you are able to read the wind well enough to accurately test tiny differences in POI during windy conditions. If that's true, you are the world champion in every class and you don't have time to waste typing on this forum.

 

[Ned Ludd]

Gstaylorg – this is that Bartlein 30” that I was talking to you about. Freebore as it turns out is .170” (sorry initial confusion on my part). MV at 45.8 grains of Varget was 2,784 fps. MV was still linear up to 46.3 grains (2,815 fps) which is as far as I went.

What you said about “being on the ball” is my only hesitation of tying to shrink the group. I am using a NF Competition but frankly not sure of my ability to consistently shoot in the twos… Just being honest....

RonAKA – appreciate your input but I am pretty much sold on OCW and an additional ladder is not in my horizon.

I see, thanks for the clarification. With that configuration, 2784 fps still seems a little fast to me for Varget. In a 30" barrel with a 185 that's about the velocity I'd expect for H4895, which in my hands usually gives about 25-30 fps greater velocity than Varget at the sweet spot. However, it doesn't sound like it's grossly overpressure. Are you using Palma brass? Regardless of the final velocity you obtain in your specific setup, the precision will ultimately tell you where it needs to be. I think you might be able to tune it finer than it currently is with a little more effort. The good news is that it sounds like what you already have is certainly useable, so you can decide how much more effort you might be willing to put into it.

FWIW - I shoot load development rounds exactly the same way I shoot in matches (prone, bipod, etc), rather than off a bench. It's simply feels more natural for me to shoot development rounds the same way I shoot in competition. When I first started doing load development, I could fairly routinely shoot half MOA groups, occasionally a little under, but that was about it. I believe the process of shooting many, many load development groups over time actually helped me to become better behind the rifle in terms of shooting smaller groups at 100 yd ( breathing, trigger control, etc.). So even load development can be put to good use as practice. It certainly won't hurt you to try and tune the load in a little better with seating depth, even if the groups ultimately remain about where they are currently. I would view it simply as more time behind the rifle, with at least the possibility for improving the load.

I'm not sure how you actually shoot your groups during load testing, but one suggestion I would make (if you're not already doing it) would be to offset your POA and POI. I usually try to put the POI about 1" to 1.5" below the POA. That way, I don't shoot out the aiming point during the process of shooting each group. I also mark a cross with a Sharpie on yellow adhesive-baked round labeling circles, which I place over the center red aiming dot of the targets I use. The bright yellow background provides better contrast with the black reticle and the cross provides a much finer aiming point. The image below is a recent seating depth test I did with the 90 VLDs (5-shot groups @ 100 yd), which shows how I set my targets up. There are certainly lots of different approaches, but I find that a fairly fine aiming point and offset POA/POI are helpful.

I'm also finding out the hard way after my recent move back to NE that the constant windy conditions here make load development much more challenging. If you're not using the small BR-type wind flags while you test, you should definitely think about getting a couple. The difference between consistent half MOA and 0.25 MOA really isn't all that much, but even the little things can add up to more dispersion, so I like to have as many of them covered when load testing as I possibly can. The more confidence I have in my ability to shoot tighter groups, the better I feel I will be able to correctly interpret the effects (if any) of changes in load parameters. In any event, it's certainly worth working on over the long run. Good luck and keep at it!