6.5x55 H4831 Hornady 140gr Match Load Development - Help!

Slug870

Slug870

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Good evening all,

So I finally got out to do some testing with the title combination and I'm a little stumped here... Perhaps someone could offer some insight.

Rifle - Tikka T3 Varmint 6.5x55 Factory Barrel 1/8 Twist
Bullet - Hornady 140gr Match BTHP
Powder - H4831
COAL (Ogive) - 2.535"
Brass - Lapua Virgin & 1F Neck Sized (both trimmed to 2.157")
Primer - CCI 200 Large Rifle

Distance to Target 315m
Conditions - Clear, +7
Wind - 20kph, Gusts to 39kph (winds at target kinda variable/swirling, winds at shooting point heavy headwind)
Chronograph - LabRadar


First up, a couple ladder tests, 42gr-44.8 in .4gr increments. First ladder shot low to high, second shot high to low. Unable to track shots on target due to mirage (which was crazy for some reason!). See data below

Ladder Comparison.jpg

As shown, there's some crazy sh*t going on there, but the sweet spot seems to be around 43.2gr-43.6gr (please correct me if I'm wrong).


Next up, we move to 5 shot groups, loads as follows;

1. 42.0gr
2. 42.6gr
3. 43.2gr
4. 43.8gr
5. 44.4gr

Note: Scope was adjusted after firing first group. No scope adjustment after first group. Circles are 3"

315m Target.JPG

As shown, the best showing is 43.2gr with an average velocity of 2365.53fps and a SD of 14.2 (again, please correct me if I'm wrong).

So with the provided data, my load would focus around that 43.2gr area. Obviously further testing has to be done in that load range left and right, as well as seating depth, got it. But here's the thing; I'm only pushing the 140gr BTHPs at ~2365fps!!! Should I not be able to get these bullets up to ~ 2600fps easily? I loaded slightly above the Hornady published max, but my brass looks good with no signs of pressure and I feel like there's another accuracy node just waiting up a little higher...

So my questions are as follows;

1. Am I interpreting the data correctly?
2. Am I incorrect in assuming my one accuracy node (shown through ladder test x2 and group) is significantly lower in velocity than what I can safely achieve?
3. Most importantly, can anyone offer advice on experience with higher charge weights with H4831 and 140gr Hornady Match BTHP? I understand I'm loading with the bullet way out there chasing the lands of the Tikka barrel, but still, there is plenty of case capacity left and I can't help but think there's an accuracy node waiting up higher.

Thank you in advance for your comments, critique and assistance.

Cheers!
 

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Last edited:
Realistically you should be able to load the 140gr BTHP in the Swede, with H4831, to 49grs +/- for 2800 fps from the 24.4" Tikka
 
Thank you gentlemen for your replies. Coincidentally, yours were the three names I had hoped to see replying in this thread.
 
Those Tikka T3 actions are very strong and rigid to boot.

I use IMR7828ssc and started my loads at 48 grains and worked up to 50 with the 139 SST bullets seated out as far as possible for my chamber. Tikka 6.5x55 rifles seem to have very long throats. My magnetospeed tells me I'm at a 2865fps average and the usual indicators of over max pressure, such as case head expansion and loose primers aren't there. The primers tend to flatten a bit but nothing serious.

H4831 is a tad faster but in my rifle, 2800 is doable without exceeding pressure limits.

I went to 7828 because it was more consistent in my rifle. Theory behind it is that the slower burn time lengthens the pressure curve.

Both are excellent powders for the 6.5 Swede but if you have one of the older milsurps, be very careful to mark you ammo as HOT. I file a very small notch out of the edge of the extractor rim.
 
Again, thank you to all who have posted.

I was aware of the 6.5x55 loads in the Hornady manual being conservative, but I didn't think they were quite that conservative, wow!

Oh well, I'll start again at 44.8 and work up to 48ish. It will be new ground for me using a starting load that is at or above published max, but I tend to do well under pressure... (yes, that was humor right there)
 
For years I ran 46.6grs H4831sc under 140gr bullets in a 260 Remington (2650-2700 fps depending on bullet, from 22" barrel) The Swede has 10% more case capacity than the 260
 
todbartell said:
For years I ran 46.6grs H4831sc under 140gr bullets in a 260 Remington (2650-2700 fps depending on bullet, from 22" barrel) The Swede has 10% more case capacity than the 260
Click to expand...

Oddly enough, I am about to start working up a deer load with my Tikka T3 Lite .260 Rem. This info is definitely good to know, thank you again.
 
I also have a tikka T3 varmint. I found 46 and 46.5gr of RL22 gives me great accuracy with 139gr Lapua scenar and they chronoed at 2645 FPS (3 shot average) This is the max load according to Nosler but I have no pressure signs on the Lapua brass.
I also chronoed 39.5gr of IMR4350 at 2435 FPS (3 shot average)
 
As has been stated already, not enough powder: I have the "same" rifle (T3 SS Varmint in 6.5x55) so in that regards it's the same but insert the usual caveat.

The following is an exceptional load in my rifle and although the powder charge is half a grain over published loading, shows no pressure issues in my rifle.

Lapua brass
47.5gr H4831sc
BR-2 primers
140gr SST or 139gr Scenar
3.165" COAL

I've loaded up to 48.0gr of H4831sc which shot just as fine, though the primers were mildly flattening so I kept the load lighter. If memory serves, the chronograph indicated about 2750fps.
 
I shoot a T3 varmint as well. I load 140 SMKs & RDFs over 46.5g RL22. As others stated above you need to get into the 2700-2750fps range. Check out Nosler's online load data, their accuracy load worked well for me.
 
Sadly I’ve not had the chance to get out and shoot, however the rounds are waiting in my gun room and my schedule has cleared up. I will shoot up to 48gr, monitoring LabRadar readings and pressure signs. I’m confident I’ll see positive results.

I’ll be sure to post results.

Cheers!


kilohertz said:
So Slug870,

How did your loading go with this round? I am loading the same powders, 7828 and H4831 and bullets and have run a few tests in my Voere. I would like to compare notes if you are interested.

Cheers
Click to expand...
 
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