Need Quickload info for 270Wby
- Thread starter wbyfan1
- Start date
- Oct 30, 2004
- 24,445
- 3,485
Not in front of my home PC but mine maxed out at about 75 gr for 3450 fps or so.......
G
Guest
Guest
I've shot that exact combo (IMR7828ssc & 130gr SST). Work up from 70gr to the max for your rifle based on the above load data (still the current published IMR data, by the way) and you'll find 3450-3500fps in there somewhere. I suspect you'll find accuracy around 73.5-74.5gr, based on my experience as well as several others results. Good luck with the loading. Post pictures!
DrMike
Ballistician
- Nov 8, 2006
- 37,542
- 6,615
Cartridge : .270 Weath. Mag.
Bullet : .277, 130, Hornady SST InterLock 27302
Useable Case Capaci: 75.157 grain H2O = 4.880 cm³
Cartridge O.A.L. L6: 3.295 inch = 83.69 mm
Barrel Length : 26.0 inch = 660.4 mm
Powder : IMR 7828 SSC
Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% 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
-20.0 79 56.40 2680 2073 31536 10347 88.8 1.553
-18.0 81 57.81 2750 2183 33740 10700 90.3 1.513
-16.0 83 59.22 2821 2297 36103 11040 91.7 1.474
-14.0 85 60.63 2892 2414 38636 11366 93.1 1.429
-12.0 87 62.04 2963 2534 41357 11675 94.3 1.384
-10.0 89 63.45 3034 2658 44280 11966 95.4 1.340
-08.0 91 64.86 3106 2784 47416 12237 96.4 1.297
-06.0 93 66.27 3177 2913 50797 12487 97.2 1.256
-04.0 95 67.68 3248 3045 54433 12713 98.0 1.217 ! Near Maximum !
-02.0 97 69.09 3319 3180 58353 12914 98.7 1.179 ! Near Maximum !
+00.0 99 70.50 3390 3317 62585 13089 99.2 1.142 ! Near Maximum !
+02.0 101 71.91 3460 3456 67156 13236 99.6 1.107 !DANGEROUS LOAD-DO NOT USE!
+04.0 103 73.32 3530 3597 72104 13354 99.8 1.073 !DANGEROUS LOAD-DO NOT USE!
+06.0 105 74.73 3599 3740 77461 13441 100.0 1.040 !DANGEROUS LOAD-DO NOT USE!
+08.0 107 76.14 3668 3884 83264 13499 100.0 1.008 !DANGEROUS LOAD-DO NOT USE!
+10.0 109 77.55 3736 4030 89528 13547 100.0 0.977 !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 99 70.50 3548 3635 76114 12640 100.0 1.054 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 99 70.50 3166 2894 50522 12794 93.5 1.257
Bullet : .277, 130, Hornady SST InterLock 27302
Useable Case Capaci: 75.157 grain H2O = 4.880 cm³
Cartridge O.A.L. L6: 3.295 inch = 83.69 mm
Barrel Length : 26.0 inch = 660.4 mm
Powder : IMR 7828 SSC
Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% 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
-20.0 79 56.40 2680 2073 31536 10347 88.8 1.553
-18.0 81 57.81 2750 2183 33740 10700 90.3 1.513
-16.0 83 59.22 2821 2297 36103 11040 91.7 1.474
-14.0 85 60.63 2892 2414 38636 11366 93.1 1.429
-12.0 87 62.04 2963 2534 41357 11675 94.3 1.384
-10.0 89 63.45 3034 2658 44280 11966 95.4 1.340
-08.0 91 64.86 3106 2784 47416 12237 96.4 1.297
-06.0 93 66.27 3177 2913 50797 12487 97.2 1.256
-04.0 95 67.68 3248 3045 54433 12713 98.0 1.217 ! Near Maximum !
-02.0 97 69.09 3319 3180 58353 12914 98.7 1.179 ! Near Maximum !
+00.0 99 70.50 3390 3317 62585 13089 99.2 1.142 ! Near Maximum !
+02.0 101 71.91 3460 3456 67156 13236 99.6 1.107 !DANGEROUS LOAD-DO NOT USE!
+04.0 103 73.32 3530 3597 72104 13354 99.8 1.073 !DANGEROUS LOAD-DO NOT USE!
+06.0 105 74.73 3599 3740 77461 13441 100.0 1.040 !DANGEROUS LOAD-DO NOT USE!
+08.0 107 76.14 3668 3884 83264 13499 100.0 1.008 !DANGEROUS LOAD-DO NOT USE!
+10.0 109 77.55 3736 4030 89528 13547 100.0 0.977 !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 99 70.50 3548 3635 76114 12640 100.0 1.054 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 99 70.50 3166 2894 50522 12794 93.5 1.257
- Thread starter
- #5
Wow! At 72.0 grains, QL is showing over max pressure. Interesting. Is the design of the Hornady bullet such that it generates higher pressure than Nosler's? Nosler's book shows 74.5 gr as the max and IMR's data shows 76.0 as max. Hmmm??
I was merely curious about the QL data as my pet load is 73.5 gr of 7828ssc with the 130 SST. This produces very tight and consistent groups coupled with a velocity of 3450 from my 26in barreled Mark V. After firing, the primer is cratered slightly and there are very faint ejector marks on the case head. Bolt has no resistance whatsoever when opening. This load is well over max in Hornady's load manual, but I put zero faith in their Wby data, as it's obivously not pressure tested in a rifle or test barrel. Thinking maybe I should back it down a bit. How much faith do guy's put in QL?
I was merely curious about the QL data as my pet load is 73.5 gr of 7828ssc with the 130 SST. This produces very tight and consistent groups coupled with a velocity of 3450 from my 26in barreled Mark V. After firing, the primer is cratered slightly and there are very faint ejector marks on the case head. Bolt has no resistance whatsoever when opening. This load is well over max in Hornady's load manual, but I put zero faith in their Wby data, as it's obivously not pressure tested in a rifle or test barrel. Thinking maybe I should back it down a bit. How much faith do guy's put in QL?
wbyfan1":17c8yu54 said:
If your getting ejectors marks, you are hammering. Not saying it is totally dangerous, but it is warm. Again, I would be the Devil if I said I haven't done that, but I think backing down a touch will extend the cases, which is more my concern with my own loading.
I use QL as a guide, same as the chrono. Along with the other signs, it all paints the picture. QL could be using a case with less capacity as well, so that is a factor. If you weighed a fired case of water, it would allow more accurate data for your rifle.
DrMike
Ballistician
- Nov 8, 2006
- 37,542
- 6,615
QuickLoad is an excellent predictor of cartridge performance. However, it is not pressure tested. The data from Hornady (or IMR or any reputable powder/bullet manufacturer) is pressure tested. Under the conditions of their tests, given the components they used from the identical lots, with the identical chamber dimensions of their tests rifles, you will get the same pressures. QL cautions that powder burn rates can vary as much as 10%, which means you are responsible to start low and work up, verifying that the load is safe in your rifle. This is the reason you do not simply pick a charge and shoot it. I rely upon QL as a predictor and as a means to get me within a reasonable distance of a maximum load. I am responsible to work up the load, watching for pressure signs and verifying that it is safe in my rifle.
G
Guest
Guest
Just about the only thing I'll add is that much of the current published Weatherby data (from major component suppliers) is not pressure tested. Hodgdon has told me they do not have a test barrel in 270Wby and all their current data in PSI (not the CUP data they publish for IMR powder) is computer simulation. I'd also add that it's carrying, in my experience, optimistic velocity estimates and a very wide safety margin. Hornady's data is watered down somewhat, as well, but I don't know whether they actually test it or just simulate it. I can tell you they have backed off of Weatherby loads markedly, while not backing off of other magnum chamberings (WinMags, RemMags, etc.) so I suspect there is a certain amount of simulation involved there, as well. I do not have admission by Hornady like I do for Hodgdon. Nosler's data I'm sure is pressure tested, and it's also just about the most accurate representation, other than optimistic velocities in some instances.
As for QL, I like it as a guideline. But for Weatherby cartridges, I've never seen it to be properly accurate, and that's across several rifles and chamberings. QL as a rule dramatically overestimates pressure and velocity in the 'bee lineup, in my experience. I believe it's the system's inherent settings for throat length and so forth not taking into account the freebore common to Weatherby chamberings. I believe that setting can be adjusted, but in my experience, most folks don't bother.
The standard rules apply, folks. Start low and work up carefully using the most recent published data for the combination you'd like to use. If you're getting ejector marks and cratering (and the cratering is only at higher charges) you've got pressure issues. Back down and you'll be fine.
As for QL, I like it as a guideline. But for Weatherby cartridges, I've never seen it to be properly accurate, and that's across several rifles and chamberings. QL as a rule dramatically overestimates pressure and velocity in the 'bee lineup, in my experience. I believe it's the system's inherent settings for throat length and so forth not taking into account the freebore common to Weatherby chamberings. I believe that setting can be adjusted, but in my experience, most folks don't bother.
The standard rules apply, folks. Start low and work up carefully using the most recent published data for the combination you'd like to use. If you're getting ejector marks and cratering (and the cratering is only at higher charges) you've got pressure issues. Back down and you'll be fine.
- Thread starter
- #9
Ah.....the old IMR sheet. I have one and will not give it up. Believe me those are max loads.
Re the freebore with wby and Quickload....Dubyam is absolutely correct that QL does not account for freebore. And from what I've heard certain years of weatherby rifles have different amounts of freebore. The only way I make up for predictions is to chrono a load and then add into quickload more "case capacity" till it matches my results. Then I work up from there using quickload simulations.
I even have a factory rem 700 308vtr that has alot of factory freebore. All my loads come out much slower than predicted till I make the case capacity adjustments in quickload.
A few years ago a buddy asked me to load some 300 wby with 180's. I took my golden load from my gun and started his loads 3 grains less. He blew the primers right out of the cases. Turns out the gun was custom made with a match grade chamber and absolutely no freebore. YIKES....that was a lesson!!
Re the freebore with wby and Quickload....Dubyam is absolutely correct that QL does not account for freebore. And from what I've heard certain years of weatherby rifles have different amounts of freebore. The only way I make up for predictions is to chrono a load and then add into quickload more "case capacity" till it matches my results. Then I work up from there using quickload simulations.
I even have a factory rem 700 308vtr that has alot of factory freebore. All my loads come out much slower than predicted till I make the case capacity adjustments in quickload.
A few years ago a buddy asked me to load some 300 wby with 180's. I took my golden load from my gun and started his loads 3 grains less. He blew the primers right out of the cases. Turns out the gun was custom made with a match grade chamber and absolutely no freebore. YIKES....that was a lesson!!
G
Guest
Guest
Always start low and work up, for sure! Safety first!
