Ready to collect mo data on 6.5 creedmoor

[D. Hargrove]

We are beginning to get into the "precision" vs "accuracy" discussion. Long Range shooters will often tell you that the difference between various types of rounds and hence their consistent performance is in the precision of the loading process. LR Rifleman generally roll their own and therefore have a certain level of precision in the process that far exceeds the standard rifle round created in mass production. Once this precision is achieved it is then possible to begin the process of obtaining the data from the rifle. Of course the factors that are constant and can be controlled by the shooter are fewer than the environmental considerations once the precision round has been created. There are more than a few articles written on this topic I am sure. If anyone is truly a Long Range junky, I strongly recommend visiting https://www.snipershide.com/ and let your brain swell with the information available there. Great topic and one that few are truly masters of. Enjoy the LR game fellas, it is a true challenge and will set you in your place quickly.

 

[Jcann]

Since all of us should strive to learn, here are two good pieces of information.
http://www.accurateshooter.com/technical-articles/calculating-bullet-rpm-spin-rates-stability/
http://www.bergerbullets.com/twist-rate-calculator/

Time and energy prevents me from expounding on this with regards to mass produced 308 ammo for the military's precision weapon system. Suffice it to say they have the key to get one type of ammo that shoots great out of hundreds of different rifles and this key is easily determined through handloading. There is a reason why the majority of custom made 7WSM rifles shoot their best (with 180gr VLD bullets) somewhere between 2900-3000 fps with a 1:8.7 twist barrel.

 

[Cowcatcher]

Since all of us should strive to learn, here are two good pieces of information.
http://www.accurateshooter.com/technical-articles/calculating-bullet-rpm-spin-rates-stability/
http://www.bergerbullets.com/twist-rate-calculator/

Time and energy prevents me from expounding on this with regards to mass produced 308 ammo for the military's precision weapon system. Suffice it to say they have the key to get one type of ammo that shoots great out of hundreds of different rifles and this key is easily determined through handloading. There is a reason why the majority of custom made 7WSM rifles shoot their best (with 180gr VLD bullets) somewhere between 2900-3000 fps with a 1:8.7 twist barrel.

Those were some good reads and handy tools Jcann. I guess I can now add an RPM column to my data log.

 

[Cowcatcher]

A few days ago I saw some 6.5cm brass for sale that was specifically marked small primer. I just kinda shrugged it off. Now since Jcann assumed I was loading small primer brass, it's got me wondering if I should add one more "variable" to my "process" by buying some. Opinions?

 

[steelfingers]

A few days ago I saw some 6.5cm brass for sale that was specifically marked small primer. I just kinda shrugged it off. Now since Jcann assumed I was loading small primer brass, it's got me wondering if I should add one more "variable" to my "process" by buying some. Opinions?

No opinion, because of a massive lack of knowledge, but anxiously waiting for comments.

 

[Jcann]

A few days ago I saw some 6.5cm brass for sale that was specifically marked small primer. I just kinda shrugged it off. Now since Jcann assumed I was loading small primer brass, it's got me wondering if I should add one more "variable" to my "process" by buying some. Opinions?

I just assumed you were using small rifle primer brass (SRP). If I were you I would continue on the path you are currently on. No reason to add an additional variable. I would focus on charge weight, bullet seating depth, maybe different powder (H4350, RL26, H4831sc). Word on the street is pierced primers with SRP brass due to the firing pin on some rifles. I don't know how much validity there is to this but I wouldn't want the aggravation. RL26 powder should give you the highest velocities but you would want to work up charge weights slowly. Good luck with the handloading and enjoy the process. You can learn a great deal if you keep good notes and record the data.

 

[dennishoddy]

As I'm into hyper velocity calibers like .22-250 and .243 WSSM the rate of twist and velocity make all the difference in the world. I've had to build two different rifles in the .243 WSSM to attain the accuracy. 1:8 for the 80-100 grain, 1:12 for the 55 grain.
I'll steal Jcanns reference about why so I don't have to type it.

you may need somewhat MORE RPM as you increase velocity, because more speed puts more pressure, a destabilizing force, on the nose of the bullet. You need to compensate for that destabilizing force with somewhat more RPM. But, as a general rule, if you increase velocity you CAN decrease twist rate. What’s the benefit? The slower twist-rate barrel may, potentially, be more accurate. And barrel heat and friction may be reduced somewhat.

Just remember that as you reduce twist rate you need to increase velocity, and you may need somewhat MORE RPM than before. (As velocities climb, destabilizing forces increase somewhat, RPM being equal.)

 

[Jcann]

My limited knowledge (I mean that) length of barrel, velocity, twist...yada, yada, and the information I've received from some of the top distance shooters, the bullet may not true for a distance. Yes wobble a bit. If this is a trick question to determine my ignorance in the subject, no need. I'm still in a learning cycle using the best info I can get and experience at the range.

No it wasn't a trick question and I would never try to prove anyone's ignorance. I will always try to help the fine people on this forum. Lord knows I've needed lots of help over the years and I've gotten it from people here, on accurate shooter, long range hunting and on snipershide

I truly didn't understand what you meant by stability. Stability is controlled by velocity and barrel twist. The loads I produce that shoot good throughout its ballistic arch are generally within a specific RPM. When they are outside of this RPM they generally don't shoot as good. Case prep, primer, powder, charge weight, bullet type/construction, seating depth, velocity, RPM, bullet concentricity, consistency, consistency, consistency,.....and barrel quality all play a part in precision/accuracy. Then it all goes to hell in a hand basket due to wind. Sometimes you just have to smile and shake your head when shooting longer distances.

 

[dennishoddy]

Then it all goes to hell in a hand basket due to wind. Sometimes you just have to smile and shake your head when shooting longer distances.

In Oklahoma that is a gimme.

 

[steelfingers]

No it wasn't a trick question and I would never try to prove anyone's ignorance. I will always try to help the fine people on this forum. Lord knows I've needed lots of help over the years and I've gotten it from people here, on accurate shooter, long range hunting and on snipershide

I truly didn't understand what you meant by stability. Stability is controlled by velocity and barrel twist. The loads I produce that shoot good throughout its ballistic arch are generally within a specific RPM. When they are outside of this RPM they generally don't shoot as good. Case prep, primer, powder, charge weight, bullet type/construction, seating depth, velocity, RPM, bullet concentricity, consistency, consistency, consistency,.....and barrel quality all play a part in precision/accuracy. Then it all goes to hell in a hand basket due to wind. Sometimes you just have to smile and shake your head when shooting longer distances.

True. I thank you for your info. That's what I looking for. I can shoot. I know guns but when I find I'm out of my league (way out ha) I look for answers from folks like you and others. I want to know as much as I can. It's the OCD thing.
Anything you can offer as help would be appreciated.
Cowcatcher, you and others here are data mines and minds.