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I chronographed a load that shoots extremely accurate in my Brux 22" barrel 260 Remington.
However, it is supposed to be MUCH faster than the velocity I'm getting and I'm very disappointed.
260 Remington
Nosler 120 Ballistic Tip
45.5 grains H-4350....average velocity is only 2700 FPS?
I have zero pressure signs, but I'm at least 200 FPS slower than expected even with 2" shorter barrel than the test barrel from Nosler.
Do I have a malfunctioning chrono, slow lot of H-4350, or a turtle slow barrel?
Suggestions??
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Give us the rest of the load.
Who's brass, what primers?
What's your fired H2O Case volume?
You didn't use logic or reason to get into this opinion, I cannot use logic or reason to get you out of it.
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Remington brass
CCI-200 primer
Unknown H20 volume
2.785 OAL
2730 average FPS
Last edited by Dixie_Rebel; 12/08/20.
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Remington brass
CCI-200 primer
Unknown H20 volume
2.785 OAL
2730 average FPS Generally, Rem brass is pretty average for velocities. CCI 200's are on the slow side. Your OAL isn't short enough that I'd expect any significant impact. The fired case volume will tell us if you have a large chamber, but won't tell us much about the rest of the barrel dimensions.
You didn't use logic or reason to get into this opinion, I cannot use logic or reason to get you out of it.
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Seems like I recall loading about that much H4350 with 130’s in RP cases with CCI 200’s and making 2820 or so in factory 22” 700 barrels. What’s book max? I’d bump charges and hunt for 2900 or pressure.
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Powder wise he's over book. Pressure wise, I don't think he's there yet:
Cartridge : .260 Rem
Bullet : .264, 120, Nosler BalTip 26120
Useable Case Capaci: 47.442 grain H2O = 3.080 cm³
Cartridge O.A.L. L6: 2.800 inch = 71.12 mm
Barrel Length : 22.0 inch = 558.8 mm
Powder : Hodgdon H4350 *T
Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.099% 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
-11.0 95 40.50 2619 1828 43644 9607 92.9 1.236
-09.9 96 41.00 2651 1873 45237 9740 93.5 1.216
-08.8 97 41.50 2684 1919 46885 9870 94.0 1.196
-07.7 98 42.00 2716 1965 48586 9997 94.5 1.176
-06.6 99 42.50 2748 2012 50343 10121 95.0 1.157
-05.5 101 43.00 2780 2060 52164 10241 95.5 1.139 ! Near Maximum !
-04.4 102 43.50 2813 2108 54053 10357 96.0 1.120 ! Near Maximum !
-03.3 103 44.00 2845 2156 56014 10469 96.4 1.102 ! Near Maximum !
-02.2 104 44.50 2877 2205 58049 10578 96.8 1.084 ! Near Maximum !
-01.1 105 45.00 2909 2255 60163 10682 97.2 1.067 !DANGEROUS LOAD-DO NOT USE!
+00.0 106 45.50 2941 2305 62358 10782 97.5 1.050 !DANGEROUS LOAD-DO NOT USE!
+01.1 108 46.00 2974 2356 64638 10877 97.9 1.033 !DANGEROUS LOAD-DO NOT USE!
+02.2 109 46.50 3006 2407 67008 10968 98.2 1.017 !DANGEROUS LOAD-DO NOT USE!
+03.3 110 47.00 3038 2459 69473 11054 98.5 1.001 !DANGEROUS LOAD-DO NOT USE!
+04.4 111 47.50 3070 2511 72036 11135 98.7 0.985 !DANGEROUS LOAD-DO NOT USE!
+05.5 112 48.00 3102 2564 74702 11211 99.0 0.970 !DANGEROUS LOAD-DO NOT USE!
You didn't use logic or reason to get into this opinion, I cannot use logic or reason to get you out of it.
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Just for reference. In my Savage 260 Rem 22" Bbl, 1/8 twist. Rem brass, CCI #250 mag primer , Barnes 120gr TTSX, 48grs Rel 26 = an even 3100fps. After several loading the primers pockets are still very snug. Not the slightest sign of excess pressure.
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I have a Sako 75 in .260 with a 22.5" barrel. With 45.0 gr of IMR 4350, Rem brass, CCI 200 and a 120 BT, I'm getting 2740 fps. It's almost a mirror to what you're seeing. I can say that my factory chamber has a long throat.
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The online max for a 120gr, per H, is 46.5gr H4350 for 2,960 in a 24" tube with R-P brass. If it were me, I'd load batches going up to 47gr or so and hunt for 2,900 in the 22" barrel. That shouldn't be out of line, considering variances in throating, bore, bearing surface, etc. But proceed with caution, using a chrono and all that jazz.
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What kind of chrono are you using?
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Not sure about the OP but I've used a CED M2 and a LabRadar.
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This is not a BT data recipe but it shows same bullet weight and much higher speeds. From Loaddata.com
120 Speer SP Hodgdon H-4350 43.5 2,814
120 Speer SP Hodgdon H-4350 46.5 2,960
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how are you measuring or weighing your charges?
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Every round is weighed using my RCBS 505 scale that I've used for many years.
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Thanks. That eliminates one thing...
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If it was the scale or chrony you'd see similar impacts across other platforms. Since you haven't mentioned that, neither is likely to be the issue.
It's most likely this relates to the chamber, throat, bore diameter.
In other words, keep pouring powder until you velocity get where it belongs, or you see pressure signs.
You didn't use logic or reason to get into this opinion, I cannot use logic or reason to get you out of it.
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Try using a 130-class bullet and see what happens. I can get around 3000 fps with several loads, using 129 Interlocks in my .260s. You should get easily over 2900 with a 22-inch barrel. Mine are 24.
You did not "seen" anything, you "saw" it.
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If it was the scale or chrony you'd see similar impacts across other platforms. Since you haven't mentioned that, neither is likely to be the issue.
It's most likely this relates to the chamber, throat, bore diameter.
In other words, keep pouring powder until you velocity get where it belongs, or you see pressure signs. Yep.... cautiously...
ttpoz
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If it was the scale or chrony you'd see similar impacts across other platforms. Since you haven't mentioned that, neither is likely to be the issue.
It's most likely this relates to the chamber, throat, bore diameter.
In other words, keep pouring powder until you velocity get where it belongs, or you see pressure signs. Will do Sniper.👍
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