270wsm and Barnes TTSX powder question

[wnc-coyote]

One thing I should point out before you start right at the rifling is that all the tsx's I'm working with are old versions from before Barnes changed from a secant ogive to a tangent ogive. I was lucky enough to know they were changing and stocked up. I do not know what effect that will have on accuracy seating on the lands. I started by picking a medium powder charge loading 3-4 each at .05,.03,.015,.005. There should be one stand out with much tighter group. When you see which one that is load one more set of the same and make sure it is not just a fluke. Then I done a ladder test at 300 yards to find a range in powder with consistent group. I found that on my rifle to be between 74.5 - 75.5 gr. so then I loaded three sets. 74.5,75,75.5. I would normally have went with smaller increments but in ladder testing it shot a 1" group within this range. I settled on 75. Because at 75.5 I got some primer cratering. all three charges shot under 1/4".

 

[Jesse09]

Well, if I don't hear from Barnes to the contrary, I think I'll start seating the TTSX at .005" and work out from there, more or less following the same procedure you did.

I have to remember that my Tikka T3 is not a custom rifle; I changed the stock, steel post bedded it and modified the trigger, but am not expecting world beating results. I'll be satisfied with between .500" and .800".

In thanks for your help I'll post my final (happy, I hope) results.

Jesse

P.S.: Just heard from the Barnes tech: He says that "in the majority" of rifles starting at .050" and working out from there will save a lot of time. I'll have to think about it, but will probably start at .005", .010", .050 and .060"

 

[Jesse09]

Here's the tech's reply:

" We recommend the larger jump, because the vast majority of the time the all copper bullet will get better accuracy with a large jump whereas the lead core bullets will prefer to be closer. It is not always the case but the majority of the time it is. As mentioned before see what your gun prefers, but I think it will save you bunch of time if you start at .050" off the lands and move farther away as you experiment."

 

[wnc-coyote]

I think you will find a load you will like pretty quickly. so far tsx's have been pretty easy to work up. Only thing I might recommend would be if you don't find a good load by the time you get out to .050 I would Probably jump out to .075 next. A friend of mine has a smoking load for his .308 with the 130tsx that he is jumping .110.

 

[Jesse09]

Okay, why not? I'll jump to your recommended .075" following .050", if indicated.

UPS says my bullets will be here, tomorrow; I'll use the next several days to work up loads while waiting for the remains of the ice storm to move out.

Jesse

 

[wnc-coyote]

I know what you mean about the snow and ice. Suppose to be -7 here tomorrow night.

 

[Jesse09]

Yes, I see you're somewhere in western N.C.; that's colder than here in the Atlanta suburbs, I know.

I was supposed to deliver my young hunting dog to the trainer today in S.C.; after seeing the forecast of 11*F, I told him we would re-schedule in March.

Stay warm.

Jesse

 

[cervus]

Will be interested to see your results loading close to lands. I found loading close to lands with barnes I had high pressure signs on a starting load, this occurred with 2 different calibers....

 

[Jesse09]

Hi, Cervus; it's really hard to know if you are .005" off the lands or actually into the lands; maybe your high pressure signs were from being in the lands; then, again, maybe not. I'll post my own results.

UPS failed to deliver my bullets, today; "adverse weather", they say.

Jesse

 

[cervus]

My starting loads were .020-.025 off lands with a 260 an 7mm08.....

 

[Shortmagman]

I have loaded Barnes TSX and TTSX bullets in a half a dozen rifles and it is my opinion that you can save yourself time and money by starting all loads 50 thousands off the lands.

The latest gun that I tried Barnes TTSX in was a Weatherby Vanguard in 270 Winchester. This is a gun that I bought for about $500, so I was trying different loads and TTSX was one of those loads. At first I did not follow my own advise so I loaded some at various seating depths without success. I then went back and changed the seating depth to 50 thousands off the lands and the very next three shot group was under 1/3 of and inch.

I had the same experience as Cervus when I loaded 140 TSX bullets too close to the lands in a 7mm-08.

 

[Jesse09]

Today on the bench was about as frustrating as it gets for me:

1. 19*F
2. 115 mile drive
3. I fired six fouling shots through my scrubbed barrel, not realizing that three of them were what should have been saved as my .005" (off lands) group.
4. My MagnetoSpeed V2 chrony returned wildly erratic muzzle velocities, some as high as 9500 fps.
5. All loads were 64.0 gns IMR 4350, seating the TTSX 110gn Barnes.
6. Here are my three-shot group sizes:

.010" off lands = .763" (two shots touching)
.050" =1.366" (with shot number 2 a flyer; shots 1 & 3 = .262")
.060" = .889" (the only true equilateral triangle)
.075" = .924" (a descending-to-the-right straight diagonal)

So, what did I learn? (I've already emailed MagnetoSpeed.) I really wish I hadn't lost the chance to shoot that .005" seating. It might have, with the .010" seating, lent some argument towards a close to the lands seating. (No pressure indications.)

On the other hand, though, the larger gapped groups also showed promise.

The chrony could have given some much needed informaton (if it was working correctly) by comparing muzzle velocity and extreme spread among all the groups.

What I think I did learn is that these bullets are going to be relatively easy to work with, unlike the Swift Scirocco II's.

So, I plan to load two groups at .005" and to repeat the other four groups shot today. Since all of these cartridge overall lengths exceed the magazine maximum, I may load a group with a c.o.a.l of 2.86"; that would give me an extreme gap to set the upper end.

I haven't decided whether to wait until I have a working MagnetoSpeed chrony or use my conventional Shooting Chrony. The MagnetoSpeed spoiled me - I got used to the easy setup and never dropping a shot.

I'd appreciate your feedback if you think I've missed something.

Jesse

 

[jlreff]

try ramshot hunter. that's what I run in the 270's I load for. gives great velocities too. if you talk to barnes, they will tell you they have had good results with ramshot's powders.

 

[Jesse09]

Thanks, jlreff; I'm not familiar with ramshot hunter; will look into it.

Jesse