Hi Forestry I'll run your numbers in the morning and post the results Cheers Ruger
Hi Forestry
I ran your numbers and the increase in cartridge length certainly reduces pressure, I wasn't sure if your ladder loads were RE 16 or 17 so did both.
Re 16 162 SST PSI MV
53.5 65330 2795
53.8 66513 2810
Re 17 162 SST
53.5 60842 2770 Below max
53.8 62025 2785 Below max
54.0 62827 2796 Below max of 63817 psi
I also ran the Duley numbers and increased the oal until I got a lower pressure although still 1340 psi above max
Re 17 56 gns 65157 psi MV 2837 fps compared to their printed load of 56 gns 60000 psi for MV 2750
Hope this helps
Cheers Ruger
Thanks - this is very interesting and very useful. Was this for 20 inch barrel length? My Tikka is 20inch and the new Kimber is 17inch.
I really appreciate you taking the time - OAL does make a huge difference eh, and it does look like RE17 (which I don’t have) has lower pressure at similar loading. Down the rabbit hole again…
Very helpful, thanks. However I think based on above GRT predictions & Duyley data and my own recent experience that there’s some significant batch to batch variation in RL17. This would explain the loads & speeds Duyleys got which on basis of GRT should be significantly over pressure. As mentioned above I was running 54.2 gn for 2830 fps 18in bbl 3.140 COL. This seems to align closely to GRT. Switch to new bottle of RL17 & definitely hot. Silly me did not chrony it, but I’m guessing it was up there. Dropped load to 54, then 53.8 still getting pressure signs. Dropped to 53.5 and pressure good……& the speed is 2830fps. So lesson learned always run chrony when fiddling with loads.
Hi Forestry, yes was with 20" barrel.
For your Kimber 17" barrel
Re 16
53.5 65351 psi MV 2678
53.8 66534 psi MV 2692 with COAL of 3.15"
From memory workshop innovation still had 5lb jugs of rl17 in stock on there site
Thanks again - I might need a different chrono as this was my Kimber 17inch data….about 100fps lower. I’ll also stop loading up until I check velocity again. OAL was actually 3.2 for this load. I don’t need any trouble !
162 SST RE16. 53.5
2577
2577
Errr
162 SST RE16. 53.8
2587
2609
2620
Hi @Ruger7mm - can I ask one more check with GRT please…..
Can you run 140 Ballistic Tips in the 17inch Kimber 284 @ 3.12 OAL
57gr of Win760
56.5gr of RE16
57gr of RE17
Thanks
Hi Forestry
Apologies for the delay as I have been away for a couple of days.
GRT Results
W760 MV 2813 62607 psi
Re 16 MV 2861 65335 psi
Re 17 MV 2854 62753 psi
Ballistic Tip 140, 17' barrel, and max pressure 63817 psi
Hope it helps Ruger7mm
Remember GRT is a model. If the Duleys were using a tool or system that accurately measured pressure their results are empirical or measured in the real world. There’s a saying that goes “all models are wrong, but some are useful”
@Ruger7mm
Went out today with a Garmin Chrono - 3 shots with 57gr Win760 and 140 BTs averaged 2814fps …..so GRT is was spot on this time. Fired 3 fairly fast and first two almost touching and 3rd off right with the hot barrel. Definitely an accurate 2 shot rifle but not a culling machine. I have 6 left so will load a few more and time to go hunting now.
Are TTSX a bit faster as the load given for those was 57gr RE17 for 2990fps.
Hi Forestry
I have inputted your data for the Barnes TTSX 140, 17" barrel and 57 gn of Re 17 and the result is PSI 70149, MV 2949 fps. It would seem a little hot. To get down to the GRT max pressure, a charge of re 17 of 55.5 gns at MV of 2861 fps, and psi of 63752 which is 65 psi below max.
Cheers Ruger 7mm
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