col/pwder charge

[pistolgrip1]

I'm thinking that sammi col's is how the powder charge is determined with consideration given to bullet weight and relative burn rates of a particular powder. if you are using a longer col could you increase your powder charge? thanks

 

[Engineering101]

Yes you can. That is why some have their rifles "throated" for a particular - usually long high BC bullet, so they can stick the bullet way out and put more powder in the case.

 

[pistolgrip1]

thanks. so how much of the bullet needs to be in the case?

 

[Engineering101]

That depends on how much neck you have. Rule of thumb is you need 1 caliber worth of neck so a .264 caliber bullet would need a neck that is 0.264" long. This is more of a guideline than a rule and it won't fail if your neck is only 0.263" long.

 

[pistolgrip1]

cool. thanks

 

[pistolgrip1]

so riddle me this batman. why does nosler load data list their 140 gr accubond using either imr7828 or rl25 have a lower (weight) powder charge than barnes load data using their 140 ttsx. it would seem to me that the nosler loads would be a higher powder charge than the barnes because the nosler is a shorter bullet (.085 shorter). what am I missing here?

 

[Lefty7mmstw]

so riddle me this batman. why does nosler load data list their 140 gr accubond using either imr7828 or rl25 have a lower (weight) powder charge than barnes load data using their 140 ttsx. it would seem to me that the nosler loads would be a higher powder charge than the barnes because the nosler is a shorter bullet (.085 shorter). what am I missing here?

It was most likely a different barrel for the test data for starters; not to mention different bullet engraving/drag forces, different lots/brands of casings, primers, powder. It's actually a wonder how most data is relatively similar and speaks to the manufacturers doing a decent job of controlling variances. The biggest reason you need to drop back and work up when changing components is variances (those that I just mentioned) and it is the same reason different books show slightly different top loads with similar bullet weights.

 

[Mikecr]

The manuals, their variances, SAAMI ambiguities, all the possible combinations and with unknowns such as local chamber dimensions, throat dimensions, distance to lands, powder and barrel temperature, bore dimensions, etc amounts to an abstract.
You gotta know this about reloading.
You should not be trying to figure out, predict, or draw rigid conclusions from published numbers. They represent only anecdotal ranges.

Reloading101 is local.
You back off & work up (with a chronograph and watching pressure signs) to see what you have.
From there you could calibrate software like QuickLoad, or shuffle through reloading books to try & find a match or reference point. But the bottom line is your best load is either a 'problem' for you, or it isn't.

 

[pistolgrip1]

thanks for the reply. I'm going to have to keep asking the same question. here's why. shot the barnes 140's today, imr7828 start load was 80.5 and worked up from there 81, 81.5 max load from barnes is 82. fps was in order 3518,3536,3536. then I shot the nosler using 75,76,77 grns of the same powder (same container) iirc 78 is max. fps in order was 3252,3292,3300. all the primers looked good. I use a coal of 3.700, 3.560-3.600 is published coal. the nosler being .085 shorter comes out to .225 of case space while the barnes comes out to .140. so maybe I could work up to 80 grns for the nosler and get 3500 fps?

 

[Lefty7mmstw]

thanks for the reply. I'm going to have to keep asking the same question. here's why. shot the barnes 140's today, imr7828 start load was 80.5 and worked up from there 81, 81.5 max load from barnes is 82. fps was in order 3518,3536,3536. then I shot the nosler using 75,76,77 grns of the same powder (same container) iirc 78 is max. fps in order was 3252,3292,3300. all the primers looked good. I use a coal of 3.700, 3.560-3.600 is published coal. the nosler being .085 shorter comes out to .225 of case space while the barnes comes out to .140. so maybe I could work up to 80 grns for the nosler and get 3500 fps?

what cartridge are you talking about??

 

[pistolgrip1]

7 stw, ruger #1. almost all my hunting/shooting is above 6,000ft elev.

 

[jsthntn247]

thanks for the reply. I'm going to have to keep asking the same question. here's why. shot the barnes 140's today, imr7828 start load was 80.5 and worked up from there 81, 81.5 max load from barnes is 82. fps was in order 3518,3536,3536. then I shot the nosler using 75,76,77 grns of the same powder (same container) iirc 78 is max. fps in order was 3252,3292,3300. all the primers looked good. I use a coal of 3.700, 3.560-3.600 is published coal. the nosler being .085 shorter comes out to .225 of case space while the barnes comes out to .140. so maybe I could work up to 80 grns for the nosler and get 3500 fps?

Keep working up until you see pressure. Books are just to give you a starting point but you have to let your rifle and components tell you where pressure is. I have always found Barnes bullets to produce higher pressures than other jacketed bullets. Quickloads see's it this way also.