Advice - COAL for 280 Mdl 70

[JimP]

I would say that because you are just neck sizing is that it isn't creating as much pressure in the case as your full length sized cases do. We are just talking mere thousands of a fraction here but when you are working with such close tolerances it does matter.

I would size the cases the way you plan on doing when you reload for your hunting rounds. If you just neck size your hunting rounds check every case through your rifles action and make sure that it chambers the way it should. If you full length size your hunting rounds you should be alright but even then when I full length my hunting rounds I still chamber everyone of them that I take hunting.

 

[Bonecollector]

I’ve read that some guys say neck sizing makes the remainder of the brass tighter to your chamber thus making things more accurate for your particular gun. Then there’s also the other thought that continually resizing the brass in full continues to compress and expand the brass can shorten the life of said brass.
Thoughts?

 

[JimP]

Just neck sizing does lengthen the life of your brass. Instead of working the whole case you are just working the neck and if you have the necks annealed then so much the better.

Also if you just neck size the case is already a perfect fit for the chamber of your rifle. But as I say this I laugh a little because I have had those same cases not being capable of cambering into the rifle once reloaded. You can ask how that happens when the only thing you sized is the neck but it happens.

 

[Bonecollector]

Interesting Jim. Thank you

 

[alaska2go]

I am going to chime in on this discussion on neck sizing only.. If you neck size only you will start to notice that the rounds will load with more difficulty in your chamber. Why ??? Because the shoulder on the brass starts to expand too far forward & thus making it harder for your bolt to turn the round in the chamber. I always full length resize but "bump" the shoulder of the round back .003 -.005 (3-5 thousands) of an inch back . This insures me that my rounds will always load easily.. If you CONSISTENTLY load every round the same you will find a load that works. Besides if you full length resize the round will fit your chamber better than neck sizing. People will argue that point but the chamber is machined to fit new brass/ loads .... I anneal all my brass to keep splitting of the necks & shoulders.

Reloading is a exact science !!!

With that said consistency is best practice. Deburr your flash holes, turn the necks, anneal, full length resize to your chamber specific round, chamfer the neck , flatten the primer pocket, weigh your bullets, i don't weigh the brass, make sure your powder charge is exact ( i use a jeweler's scale more precise) and you will see a big difference in stringing & groups. I can reload bullets for my buddies guns that shoot 1.5" groups with factory ammo & turn them into .5" group gun by the time I am done. Granite some guns I adjust the triggers, pull it out of the stock & bed it, and tork the screws . Most of all scrubbing the barrel and thoroughly cleaning it !!! But most part doing the process of finding where the brass is at it 's sweet spot w/ the shoulders bumped & COAL I can "usually" make just about any gun shoot well. With time & experience you will get the hang of certain bullets & their tendencies no matter what caliber it is.

Speed is exciting BUT accuracy is what stories are told. You don't hear of people bragging about a gun that shots 3300 FPS but shoots 2" groups. You hear about the gun where you can shoot a nat off a mosquito's ass at 100 yards.

Know where your gun shoots at 200 yards period.... with a chronograph & the calculators that are there on the web you can be really close to know where you gun will shoot 300-700 yards. You just have to do the field work to verify.

Rules of thumb
shorter barrel needs quicker burning powder
Ball powder needs magnum primers
long & heavier bullets need a faster twist
just because it shoots well in another gun doesn't mean it is going to shoot well in yours

 

[Bonecollector]

All good stuff thank you Alaska! I don’t disagree with accuracy over speed. I’ve nearly got this gun dialed in as I stated. I’m shooting well, well below Moa but I’m just having fun tinkering and all of the knowledge on this forum really helps to not only reduce the learning curve, but steer the learning curve and for this I am very much appreciative to everyone.

 

[Bonecollector]

UPDATE for those following and willing to school:

I fully resized the brass. Loaded 68.2 gr powder (3165 f/s) and Loaded 68.3 gr of powder (3150 f/s). What I found was more powder was slower average speed.... The fastest load was 68.0 gr (3180 f/s). All these loads were with the same loading specs with the exception of powder.

For those interested: the neck-sized only rounds at 68.2 gr were (3170 f/s).

Is it possible the brass can stretch more during additional resizing and firing process thus reducing the internal combustion & velocity? Is it possible I've found the node at 68.0 and velocity is receding a bit before it will it will increase and leave the accuracy node?

I'm simply trying to find logic. Thoughts anyone?

 

[Colorado Cowboy]

Necks can definitely stretch. Check your oal case length.

 

[Slugz]

http://precisionrifleblog.com/2012/07/20/chronograph-accuracy-tips-15-practical-tips-to-increase-accuracy-reliability/

BC......not sure of the model chronograph you are using......but just in my humble opinion.......you may check if your FPS numbers above are all within the margin of error of the equipment.

Attached is a pretty good read my bench rest crazy friends swear by. Key word...crazy...but love em as they have taught me a ton.

 

[Prerylyon]

+1 for the chrono concern.

I have a shooting chrony; its low end and tempermental, but can give accurate readings within its design limitations and giving TLC on the alignment and setup.

I was ready to toss mine til I read that piece 'Slugz shared and several others; along with doing a side by side comparison on my rifle, with a known good load, using my friend's magneto.

I have to put my chrony out 15' ahead of my muzzle to avoid muzzle blast and make sure its level in 2 planes to get reliable readings. The diffusers are a must in bright sun; and if partial, strong shadows are cast on the photo sensors, that too can give it fits. Bullet also needs to fly thru its sweet spot.

Guys see me with a tape measure, level, and laser setting up my chrono at the range. I get strange looks-but, I also have had guys struggling with theirs, ask to shoot at my bench to chrono their loads after they get frustrated. [emoji6]


This is another link with a very detailed chronograph study; scroll down the page, you'll find it, the pdf download is free. Its called, 'chronograph performance review'.

http://appliedballisticsllc.com/ballistics-educational-resources/articles/

Maybe see if you can test the loads with another friend's different model chrono, like an Oehler or Magneto?

Regards,

Sent from my SAMSUNG-SGH-I337Z using Tapatalk

 

[Bonecollector]

Necks can definitely stretch. Check your oal case length.

During these tests I've been double checking everything. AOCL is spot on. Thanks CC.

 

[Prerylyon]

Any of you seasoned reloader's ever heard of a powder's "breakover point" or have any knowledge of it?

Is it a real phenomena?

I have seen it mentioned in relation to similar reductions in velocities as 'BC is experiencing with a larger charge wgt in a given powder.

Regards,

Sent from my SAMSUNG-SGH-I337Z using Tapatalk

 

[Bonecollector]

Thanks Prerylon- for what it's worth I'm using Aliant R-26

 

[Colorado Cowboy]

Any of you seasoned reloader's ever heard of a powder's "breakover point" or have any knowledge of it?

Is it a real phenomena?

I have seen it mentioned in relation to similar reductions in velocities as 'BC is experiencing with a larger charge wgt in a given powder.

Regards,

Sent from my SAMSUNG-SGH-I337Z using Tapatalk

Never heard or it. I'm kinda funny in my approach to reloading....old school & if it ain't broke, don't fix it. My loads for my 30-06 & 25-06 were developed over 40 years ago. They still perform to my expectations, so I don't screw around with the loads. When I got my .300 Wby, it took me a long time to get it where I was satisfied with it's performance. The only time I would look at a new load would be if I couldn't get one of the components (powder, bullet) any more.


When you have a load (and gun) that performs like this, why screw with it. Just shoot it and enjoy!

 

[Bonecollector]

Never heard or it. I'm kinda funny in my approach to reloading....old school & if it ain't broke, don't fix it. My loads for my 30-06 & 25-06 were developed over 40 years ago. They still perform to my expectations, so I don't screw around with the loads. When I got my .300 Wby, it took me a long time to get it where I was satisfied with it's performance. The only time I would look at a new load would be if I couldn't get one of the components (powder, bullet) any more.
View attachment 22268View attachment 22269

When you have a load (and gun) that performs like this, why screw with it. Just shoot it and enjoy!

I can't disagree with your statement CC. BUT, I need to get it there first. You are quite the marksman and I hope to achieve the accuracy you're getting with your rifles (Nice work to you- kudos)

It's also fun to tinker and learn new things as I am doing now so that I can shorten the learning curve when I start to reload for my other rifles as I'm still working on my first rifle with less than 1 year of reloading under my belt.