Just picked-up my new 25DTI on Thursday from Dtech and I'm preparing to go to the range. Mike gave me a QL printout of the various powders and bullet weights for the 25DTI.
In looking at the % of case fill and % burn, is there a way to interpret the data that would also predict the best accuracy? I'm going to use 87gr and 100gr Sierras Spitzers only.
No it does not predict accuracy. For the most part it mainly helps with powder selection and velocity prediction. You need a Chrony to accurately measure velocity and standard deviation. Usually my lowest SD is the most accurate.
Also depending how Mike has his setup can determine low max loads. What I mean by that is variances in fired case capacity and seating depth can give you a max charge that is actually well below true max pressure. I end up usually 10-15 % higher that what the software predicts as a max pressure load without any visible signs of pressure. Keep that in mind when working up your loads.
I sure with it would but it doesn't. As WC mentions above volumes are different. As an example the computer models 29.0 as capacity on a 6X45 yet when you measure real world cases you get from 31.0 to 32.8. My current one is 32.8 and when you adjust the numbers for capacity the pressures get down to observed/guessed at very quickly.
It's a great tool for what if on the dry run bench and gives some ideas how different powders MAY work but that's it.
WC & GL thanks for the great(!) responses! Very informative! Now that I'm smarter than I was minutes ago; I have another question.
I think it was WC who said he finds QL's max load prediction to 10-15% or more low. For me that comes as good news.Meaning My goal is to be able to propel a 100gr Sierra at 2900fps in cold weather. If I can do that I'm gonna really be jazzed!
However in all of the postings it seems others are struggling to get past 2800fps.
Should've mentioned I'm working w/ my new 25DTI w/ 18" barrel. Just picked it up last Thursday.
Originally Posted By: KahunerWC & GL thanks for the great(!) responses! Very informative! Now that I'm smarter than I was minutes ago; I have another question.
I think it was WC who said he finds QL's max load prediction to 10-15% or more low. For me that comes as good news.Meaning My goal is to be able to propel a 100gr Sierra at 2900fps in cold weather. If I can do that I'm gonna really be jazzed!
However in all of the postings it seems others are struggling to get past 2800fps.
Should've mentioned I'm working w/ my new 25DTI w/ 18" barrel. Just picked it up last Thursday.
Your thoughts?
Kahuner
Yes WC alluded to that and you do run into this issue frequently. You don't always pick up 10%- 15% more velocity but you do pick up some in many cases. The velocities listed are quite conservative in some combinations compared to real world numbers.
The smart man will get a case capacity and start looking for similar sized cases to get a feel for MAX loadings. You have a good one in that the 6X6.8 or MM's 6DTI are well worked over. You know going in that any of that data is directly transferable to the 25 DTI as while case capacity is almost identical the larger 25 bore case expansion ratio is a build in pressure reducer so you can take the MAX 6 MM version loads and start at those with same same bullet weights, and bullet construction, and do well for baseline data.
I designed the BHW 25X6.8 cartidge and if you look around there is a ton of data out there that you should be able to use straight across with your new acquisition. Mike builds nice stuff and knows his away around the AR beyond a doubt. You have a deer killer deluxe there.
The guys doing 2800 with a 100 are getting about all you're gonna get. Not shabby out of an 18" tube. The 87's might be a better choice if you need to step out a tad but for most Gopher State stuff where I grew up that 100 will carry the mail for you. A 250/3000 can be matched with a 25 Sharps and this one is a step up from that. Great choice.
