260 velocities - bit slower than expected

[John MH]

Agreed, its works in my application and could probably put all ten rounds in the 5 ring (100mm circle) of a Fig 14 snap shooting at 600 yards if I did my part.

[Swarovski1]

I wanted the extra velocity for 1000yds john

[phaedra1106uk]

When I bought my Tikka T3 in 260Rem the seller recommended using 37gr of N140 behind 140gr A-Maxs, it's not a published load but he reckoned it was spot on. Having had a bit of play at various charge weights I loaded up a batch at 36gr using Nosler Custom Competition 140s loaded to 2.79" (max mag length) and took them out for a try today at Ponteland range.

 

After shifting the scope forward and sorting out the new butt stock I managed to get some pretty good groups in a 15mph cross wind. First group is 4 shots, second is 10 shots, both at 100yds which for me is pretty good as I have physical problems and lying prone is not a great position for me to spend any amount of time in!.

 

 

[Swarovski1]

I've had great results from the nos 140gr cust comp bullets, dont use them because the bc isnt as good as the others out there for 1000yds

[phaedra1106uk]

I use both the 140gr 6.5s and the 168gr .30s, both work very well for me with the added advantage of a considerable cost saving over other bullets as I get them from Europe for around 19p a bullet.

[dashed]

Again, thanks for all the replies and advice.

 

Laurie - what are your thoughts on best powders to try next? N150? Varget? Happy with current load but might have a play with some faster powders over the next few months (if I can find some to try and don't have to buy a full 1kg of Vhit powder that I don't know whether it'll work!!).

[Laurie]

With 120-130gn bullets, I'd give N150 a try. It's marginally fast-burning for 130s, so you have to be careful with charge weight increases as you approach top loads. Viht 550 should give much higher MVs, but I've sometimes found odd results especially in short barrels such as a lot of muzzle blast and flash in lower charge weights.

 

Reload Swiss RS62 may turn out to be the 260 powder. I'll try it later this year in 6.5X47L and 260 with 123s and in 6.5 Creedmoor with 120s to 140s to see if it lives up to its promise.

[dashed]

Thanks - will hunt down some n150 and give that a go...

[dashed]

Next question...! Anyone have any N150 load data? Struggling to find anything for 130gn bullet in the manuals - N150 loads only seem to be given for the much lighter bullets (108gn).

 

Thanks in advance

[Scotch_egg]

With 120-130gn bullets, I'd give N150 a try. It's marginally fast-burning for 130s, so you have to be careful with charge weight increases as you approach top loads. Viht 550 should give much higher MVs, but I've sometimes found odd results especially in short barrels such as a lot of muzzle blast and flash in lower charge weights.

 

Reload Swiss RS62 may turn out to be the 260 powder. I'll try it later this year in 6.5X47L and 260 with 123s and in 6.5 Creedmoor with 120s to 140s to see if it lives up to its promise.

Laurie, please excuse my ignorance but I use N150 in my .308 along with N140 and varget.

 

 

With people using varget and N160 in the .260 I had planned using N150 for the 139gr bullets. Reason partly being supply but also hoping for a higher velocity than N160 loads.

[Laurie]

Very few manuals quote N150 loads veering towards N550 instead as the 'high-energy' version gives so very much higher MVs and velocity is what sells everything including handloading data manuals and bullets, especially in the American market. (At the same time there is a persistent leitmotif in American forums about short 260 Rem case life especially from Remington brass and whilst N550 often gives really good results and impressive MVs from the smaller 6.5s, it's also impressively easy to 'overcook' pressures with the powder especially in North America where it can be susceptible to pressure increases in hotter conditions than we'd expect to see.)

 

The only printed manuals that I have which quote the powder in the cartridge are Lyman and Sierra.Lyman quotes 36.5-40.5 for the 120gn Nosler Ballistic Tip and gives it the 'most accurate' accolade for this bullet. Sierra quotes 35.5-39.5gn for the 120gn SPT and HPBT MatchKing bullets; 33.9-39.9gn for the 140gn SBT, HPBT MatchKing and 142gn HPBT MatchKing (Remington case / Rem 91/2 primer, the latter a hot cap for both companies' data). Sierra also gives N150 its 'accuracy load' description in this case for the 140s (37.9gn / 2,600 fps).

 

Here's what QuickLOAD says for N150 with the 130 Berger VLD in a chamber throated optimally for that bullet using the standard 2.800" COAL and using default values:

Cartridge : .260 Rem
Bullet : .264, 130, Berger VLD G7 #26403
Useable Case Capaci: 45.421 grain H2O = 2.949 cm³
Cartridge O.A.L. L6: 2.800 inch = 71.12 mm
Barrel Length : 26.0 inch = 660.4 mm
Powder : Vihtavuori N150

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms

-10.0 92 36.36 2595 1944 43853 7073 100.0 1.430
-09.0 93 36.76 2619 1981 45244 7115 100.0 1.410
-08.0 94 37.17 2644 2018 46678 7155 100.0 1.391
-07.0 95 37.57 2668 2055 48156 7194 100.0 1.371
-06.0 96 37.98 2692 2093 49681 7233 100.0 1.352
-05.0 97 38.38 2717 2130 51253 7272 100.0 1.334 ! Near Maximum !
-04.0 98 38.78 2740 2168 52875 7310 100.0 1.316 ! Near Maximum !
-03.0 99 39.19 2764 2206 54548 7347 100.0 1.298 ! Near Maximum !
-02.0 100 39.59 2788 2244 56274 7385 100.0 1.281 ! Near Maximum !
-01.0 101 40.00 2812 2282 58056 7421 100.0 1.264 ! Near Maximum !
+00.0 102 40.40 2835 2320 59895 7457 100.0 1.247 !DANGEROUS LOAD-DO NOT USE!
+01.0 103 40.80 2859 2359 61793 7493 100.0 1.231 !DANGEROUS LOAD-DO NOT USE!
+02.0 104 41.21 2882 2397 63754 7528 100.0 1.215 !DANGEROUS LOAD-DO NOT USE!
+03.0 105 41.61 2905 2436 65778 7562 100.0 1.199 !DANGEROUS LOAD-DO NOT USE!
+04.0 106 42.02 2928 2475 67870 7596 100.0 1.183 !DANGEROUS LOAD-DO NOT USE!
+05.0 107 42.42 2952 2515 70032 7629 100.0 1.168 !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 102 40.40 2913 2450 70712 7215 100.0 1.171 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 102 40.40 2716 2129 49147 7768 99.6 1.351

 

Usual warnings about QuickLOAD results and working up charges from 10% down on maximum apply.

 

40.4gn is the highest charge that is calculated to produce pressures under the CIP max of 60,190 psi. How the barrel is throated and therefore how deep the bullet is seated can affect the results considerably - beware!

 

It ties in with my own 260 where I've ended up with 40.5gn N150 in Lapua brass and the F210M primer with the 123gn Lapua Scenar which shoots very well indeed to 900 yards from a rebarrelled FN SPR factory rifle (30-inch Bartlein).

 

QuickLOAD matches Sierra's 140/142gn N150 data with the maximum load for the 139gn Lapua Scenar at 2.800" COAL also 39.9gn N150 for a calculated 2,743 fps from a 26-inch barrel.

 

(For those looking to 'push' 260, 308 Win Palma brass can be reformed to 260 with a single pass of the case through a 260 FL sizer die.)

[dashed]

Thanks Laurie, that's fantastic - very grateful!

[Scotch_egg]

Laurie, as always you are a wealth of knowledge. I think I will give the N150 a go. It will be from a short, in your book, 26" barrel.

 

I will be loading to 2.9