ok, so I've always been used to gathering data, setting up charge weights and shooting but I've stumbled on the discussion of obt. Anyone use it for load dev? Most any info I find on it is written for 18+ barrels. I was thinking more 14.5 - 11.5. If nothing written out there, where's the best place to find info?
- Thread starter Sincerd
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so basically an OCW/node/flat spot
however you find it you're looking or the same 'thing' ; a point where small variances in powder charge, be it 1 kernel or .1gr, in either direction has the least impact on the vertical spread down range
however you find it you're looking or the same 'thing' ; a point where small variances in powder charge, be it 1 kernel or .1gr, in either direction has the least impact on the vertical spread down range
OBT is different process than OCW.
There's an equation at the bottom of this website page that give you what you're looking for.
There's an equation at the bottom of this website page that give you what you're looking for.
The two are connected. OBT is the explanation for why OCW works. Chris created the OBT theory to validate the OCW method. The model was then used to try to predict which load will be the OCW without actually doing the test. The OBT model has been picked up by a couple companies and incorporated into their products. The two I know of are pressure trace and quickload. I have not messed with either of them, but came across all of this information when trying to understand load development in the 2005 era.
I read Saturdays link and...yea. pretty involved. I don't have quickload because my computer isn't stuck in the 90s and dosent have a CD drive. What are my other options?
I feel like there should be a table or graph or something listing these for different barrel lengths
I feel like there should be a table or graph or something listing these for different barrel lengths
I'm sorry that I can't be more helpful, but if you search for practical riflery forum there is a lot of stuff posted in there. At one time there was an excel spreadsheet floating around to help. I never trusted it and always defaulted to doing ocw testing and proving the load at distance. There is also a ton of info on Dan Newberry's ocw site, but he has changed it numerous times and the info seems to come and go except for the basics. I really like Dan's no bullshit approach to load development and shooting in general. He is innovative and analytical and has figured out how to accomplish a lot with very little expenditure on equipment. Also, if you haven't done it, read through the rest of Chris Long's stuff. There are some good nuggets hidden in there if you take the time to find them and digest them.
You may find this of interest:
www.tapatalk.com
Let me know if you have trouble getting there. This is a discussion of OCW and OBT by Dan and a link to Chris’s paper.
Practical Riflery and OCW Forums-OCW and Statistics
Dan, Have you investigated the statistical significance of your method? I think that the theory behind your approach is valid, but the method used to
www.tapatalk.com Let me know if you have trouble getting there. This is a discussion of OCW and OBT by Dan and a link to Chris’s paper.
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Anyone able to run a QL spreadsheet for 14.5 and 11.5 for...
77smk and
PowerPoint varmit
8208 xbr
Cfe 223
Tac
RL15
Would be greatly appreciated. If not, I get it. If anyone has the time, would be amazing.
One of these days I'm going to have to break down and buy QL
77smk and
PowerPoint varmit
8208 xbr
Cfe 223
Tac
RL15
Would be greatly appreciated. If not, I get it. If anyone has the time, would be amazing.
One of these days I'm going to have to break down and buy QL
Since you are looking at the 77 SMK in 223 I would suggest you look at Johnny's Reloading Bench on Youtube for his Mk 262 videos. Your barrel lengths will not significantly affect the results. His videos cover most if not all of the powders you mention. It should give you info on where you should find your nodes.
DO NOTE DUPLICATE his loads but work up to those loads carefully watching for pressure signs.
DO NOTE DUPLICATE his loads but work up to those loads carefully watching for pressure signs.
I have been playing with OBT stuff for a while. The newest version I have done is combining a couple data sources. I learned at shot show an easy way to find the area to shoot is to find a safe max (front side of max, not in it) for your rifle and back off 1.5 grains +/- and it will shoot around there. I took this a step farther. I captured velocities (labradar) during pressure test and then trued Quick Load. I found a .5 (I think it was actually a 4.5 node in calculator) barrel time that matched around the 1.5 grains back from my safe max and it shot great. This node seems to work in most of my rifles. The only one that was on the whole# node (4/5 don't remember which off top of my head) was the 338 Edge.
For number example, I shot up to 44 grains of RL16 in my 6.5 creed with the 144 LRHT. I had a mild stiffening of the bolt at 43.5 (not super significant, but I noticed it) and half moon ejector mark and mild bolt click at 44. I called 43.5 safe max. Looked around 42 for barrel time. 42.2 OBT matched. I ran that. Was 2905 with a .6/2 SD/ES numbers. Shot it at distance and ran great. Was not a great group at 100 but sub moa. (so it can be refined if desired) I fired 8 shots in pressure test and matched the OBT from there. Fastest load development ever. I have done this with 4 rifles now and it has worked every time.
Out of curiosity I looked at previous Satterley tests, ran a pressure test for the 142 SMK. 42 was the load for it and it also lined up just left of center on flat spot in Satterley test. So it seems to me these all identify the same area to shoot, just a matter of how you want to get there. Also, the most important part of this is you MUST have a solid loading routine. This is a BS in BS out routine and most folks have issues with it due to not having a repeatable, solid load process. Consistent neck tension and powder drop are very important for these development systems to work right.
For number example, I shot up to 44 grains of RL16 in my 6.5 creed with the 144 LRHT. I had a mild stiffening of the bolt at 43.5 (not super significant, but I noticed it) and half moon ejector mark and mild bolt click at 44. I called 43.5 safe max. Looked around 42 for barrel time. 42.2 OBT matched. I ran that. Was 2905 with a .6/2 SD/ES numbers. Shot it at distance and ran great. Was not a great group at 100 but sub moa. (so it can be refined if desired) I fired 8 shots in pressure test and matched the OBT from there. Fastest load development ever. I have done this with 4 rifles now and it has worked every time.
Out of curiosity I looked at previous Satterley tests, ran a pressure test for the 142 SMK. 42 was the load for it and it also lined up just left of center on flat spot in Satterley test. So it seems to me these all identify the same area to shoot, just a matter of how you want to get there. Also, the most important part of this is you MUST have a solid loading routine. This is a BS in BS out routine and most folks have issues with it due to not having a repeatable, solid load process. Consistent neck tension and powder drop are very important for these development systems to work right.
Yep I'm actually a patron. He did a great series. Just didn't think obt/ocw would translate from a 18 to a 14.5.
If you are using the OBT calculator, you have to enter in your actual barrel length. Measured from bolt face to crown.
You're not the first person to have that particular complaint about QL. NECO (the US distributor) claims that the issue is related to German import/export restrictions related to firearms stuff (similar to ITAR) that prevents them from using digital delivery.
I have an external CD/DVD drive that I keep around for the odd software install, and/or ripping old movie DVDs, that sort of thing. Not too expensive, and comes in handy for stuff like this. It's an additional expense, though.
Another option might be GRT... aka "Gordon's Reloading Tool" which is *much* newer and under active development, but the bullet and powder database is much less comprehensive than QL. They do have a mechanism in place for user submitted powder templates, for powders that manufacturers refuse to share the burn rate data for (Alliant 2000MR, I'm looking at you!) which could prove interesting. But they have a built-in 'tool' for working with OBT node calculation, including half-nodes.
Interestingly enough... GRT is *also* German-based... and they don't seem to have the same 'problems' with digital downloads as QuickLoad...
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