Load workup II - Post Mortem

[Hans Gruber]

So I went to the range today and shot the loads that I described in my previous thread here:

http://www.calguns.net/calgunforum/showthread.php?t=171971

I have drawn some conclusions:

1. The 168g SMK actually prefers a bit of jump in my rifle. Moving the seating out .030" to 2.830" actually caused my groups to grow.

2. 42.0g of TAC at 2.800" seems to be the trick. As I worked up to 43.0g I only got the most tiny inkling of primer flattening (to the point where my eyes may have been playing tricks on me) and the accuracy faded a bit between 42.0 then back together at 42.8. I think I'll stick with 42.0 for wear and tear purposes.

3. My loads for the Barnes TTSX 168g completely crapped the bed. Absolutely aweful. 2" was my best "group" and it spread to 6" and off of the grid for one set.

My TTSX recipe was:

FGMM brass - once fired and trimmed to 2.005 by me
CCI 200 LR Primers
40.5 - 43.0g of TAC
Seated to 2.830 as instructed by Barnes (.050 off of the lands)

Any ideas? Can the TTSX be salvaged for my rifle or should I be looking at other options with such a poor result?

[buffybuster]

Any homogeneous bullet is going to be particular. One of the reasons is that they are, by bullet standards, quite hard and they will not slug up in the bore like most conventional bullets will. As a result, if your bore is on the oversize side, they will not shoot too well. They are also less tolerant of bore irregularities.

Might want to try another model or maybe a slower powder.

[NRAhighpowershooter]

Might want to try another model or maybe a slower powder.

Varget......................

[buffybuster]

Varget......................

or Reloader 15

[Hans Gruber]

Maybe I'll give Barnes a call, see what they suggest. I'd really like to stick with TAC for now if I can. Maybe I read their instructions wrong. Maybe 0.050" off the lands is supposed to be 0.005?

It sucks to fail so badly after having pretty good success with the SMK 168's. On my first group I had 3 SMK's all make a .25" group. Of course I spoiled the photo op with a flier that I chalk up to myself.

[westcoastr]

Maybe I read their instructions wrong. Maybe 0.050" off the lands is supposed to be 0.005?

.05" is correct but that doesn't mean your rifle will like it. test a long med and short to see.

TTSX 168 are freaking LONG. so with powders less dense than say TAC or BLC-(2), you are going to end up with compressed loads at moderate levels.

i've have not got 168 TTSX so shoot very well either. typically 1.5" groups. I would load up a couple groups at shorter COALs, try them out, and call it good.

waiting to get some e-tips and the new hornady to see what they can do. I have had very good luck w/ the Barnes MRX's, but at $1.50 per pill it can get pricey.

[Hans Gruber]

Just got off of the phone w/Barnes. The guy suggested trying .030" and .080" off of the lands to see if it likes either one more. Powder didn't come into the conversation beyond me telling him what I use so they didn't think it was much of a factor.

Guess I'll order another box and give it one more go.

[Hans Gruber]

I just had a thought. Is it possible that I didn't have enough neck tension on my TTSX loads? This was the first time I was using the FC brass. I resized using a .337 bushing and am now wondering if I screwed that up. I was just able to push an SMK into a case far enough to make it require some effort to pull it back out. I did hand test tension on the TSX's once seated and they didn't SEEM to want to go anywhere but I didn't really test it too much either.

I resize my GFL (Fiocchi) brass using a .333, any thoughts on resizing my FC brass with that to see if I get better results? What usual bushing sizes do you other .308 loaders use typically? Just in general. I'm not sure if I'm way off or not.

[westcoastr]

I just had a thought. Is it possible that I didn't have enough neck tension on my TTSX loads? This was the first time I was using the FC brass. I resized using a .337 bushing and am now wondering if I screwed that up. I was just able to push an SMK into a case far enough to make it require some effort to pull it back out. I did hand test tension on the TSX's once seated and they didn't SEEM to want to go anywhere but I didn't really test it too much either.

i use .335 and .336 bushings but .337 might be fine, it is brass/pill dependent. but you were able to seat the pill with just your hand?? if so that is too loose.

unless you have a chrono, which might show a large velocity spread, you will have to resort to trial and error. try a tighter neck and see what happens, being cognizent of pressure signs.

[Hans Gruber]

I have a feeling that the hardness/slickness of the all copper bullet probably has something to do with it as well. I did a bunch of reading last night and it seems that the Barnes bullets like to have some neck tension on them. When I seated them it took total minimal effort to move the press, gravity + a pinky.

Maybe I'll just zap em with the .333 to be sure. I'm not super concerned about case life as I realize that I'm going to have to go out and buy some decent cases eventually anyway.

Thanks again! I think that once I get to the bottom of this I'm going to post links to all of my newbie posts as a compendium of the thought process of working out loads for dummies

[jdberger]

I think that once I get to the bottom of this I'm going to post links to all of my newbie posts as a compendium of the thought process of working out loads for dummies

Please do.

[VtotheZ]

Great info!

[Hans Gruber]

Anyone know if rapid deterioration of accuracy at increased powder load is indicative of another condition?

I was just looking at my targets from Sunday and noticed that the spread looked like this:

42.6: 2.5"
42.8: 3.5"
43.0: 5.0"

These were rounds 35-50 fired through a clean barrel. These groups were all over both vertically and horizontally. Could this be a clue? I'm developing my load plan for this weekend and I don't know how far I should chase down neck tension vs seating depth.

[buffybuster]

Anyone know if rapid deterioration of accuracy at increased powder load is indicative of another condition?

I was just looking at my targets from Sunday and noticed that the spread looked like this:

42.6: 2.5"
42.8: 3.5"
43.0: 5.0"

These were rounds 35-50 fired through a clean barrel. These groups were all over both vertically and horizontally. Could this be a clue? I'm developing my load plan for this weekend and I don't know how far I should chase down neck tension vs seating depth.

One possible cause that comes to mind is the beginning of excessive pressure.

If accuracy really begins to go south with relatively small increases in powder charge, that can be an indication that you've exceeded the pressure limit that your action is comfortable with. Meaning the action/bolt is beginning to distort enough to impact the accuracy. Small increases in powder charge can have an asymmetrical increases in chamber pressures.

If you were running the same powder charges for your conventional 168gr bullets and your Barnes TSX, I'm guessing your pressures for the TSX were considerably higher.