Which barrel profile would act stiffer?
- Thread starter darkangel_r2
- Start date
That's what I currently do when I load in batches. Every time I load up a batch I re-zero and get some velocity stats to see if it changed much. 5-7 shot group for every 1-2 hundred loads. It moved some with the 308 that I started on but I have done a better job controlling my 6.5 creed and it moved very little per batch.
While I agree 100% that low stress and internal dimension consistency are indeed critical, the weight of the barrel does indeed matter and it's more than just resistance to heat. The heavier contour barrels dampen vibrations better. Dampened vibrations allow tuning nodes to be wider and allow more flexibility in load selection.
Also, reducing the diameter of a barrel blank can cause the interior diameter to enlarge, and the more contouring the more likely of that happening. Thus a lighter contour barrel has a greater chance of having internal inconsistency.
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Any of the barrel profiles listed would likely provide more than adequate group size. The question is since this is a gun that is going to see significantly varied conditions out doors while shooting I want to pick the one that acts the stiffest. Where there is the least shift in POI if my reloads fall out of a node due to changing conditions.
When I was working with my friends sporter profile I could see 1 1/2" movement between charge levels that were only .4gn apart in a 30-06. It produced a nice reliable group with the charge we settled on but im concerned that a barrel of that profile might start throwing shots 1 1/2 inches away from POA if conditions change enough. So I want to know what barrel profile in the 4lb at 24" range would act the stiffest (make all shots durring load dev stay as close as possible to the same POI)
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Cloudrepair
Silver $$ Contributor
A Cut barrel will have less stress induced so stress releaving will have better results.
Just my thoughts though.
Is dimensional consistency when removing barrel material completely controlled by stress relief or does rifling method itself contribute to it?
interesting.
No. Button rifling adds a lot of stress. Cut rifling not so much. @Stan Taylor can describe all this more thoroughly.
That said, any good quality barrel from a reputable manufacturer will likely shoot well.
BoydAllen
Gold $$ Contributor
Do both rifles have their actions bedded and barrels floated?
Barrels are floated, but neither has been bedded.
I sold the 308 to my brother in law and its now in an alum chassis. Can you do a bedding job in a chassis? Does it help in a chassis? We are still doing lead dev on that gun as we replaced the barrel with a reduced freebore 7.5 twist 6.5 creed to shoot the sierra 150s.
The 12 lrp is in its factory HS precision fiberglass stock with aluminum bedding block. Can I bed that?
CharlieNC
Gold $$ Contributor
I don't think there is a definitive answer to your question in terms of one of those profiles providing a better node to offset environmental and loading deviations. All of the profiles you noted are known to perform very well with respect to your concerns. As long as you get one of decent quality, other variables will dominate. You should be able to maintain +/-0.1gr with an average scale and stay reasonably within a properly developed node. Proper bullet and powder are of major importance.
Retired Grunt
F Open Shooter
There is no need to bed a chassis, they can be torqued pretty tight. I have a Savage 12LRP in a MDT Tac 21 and it is set. It came in a H&S with the aluminum block, i never bedded it, kind of the same a chassis. I did read here last year or longer someone did bed the block.
BoydAllen
Gold $$ Contributor
Chassis stocks can be bedded. Factory actions are machined before hardening which warps them very slightly, with the result that you are putting a slightly distorted action into milled bedding that is straight, but does not fit perfectly because of the action distortion. I know that this will come out of left field but go do some, make that quite a bit of reading and viewing at http://erniethegunsmith.com/ His method for bedding aluminum bedding blocks works very well, and is based on sound principles. I would think that the same thing would apply to a chassis. I would never do much serious load development without first bedding the action. You need to have a good foundation to work from. Would you build your house on fresh, uncompacted fill?
Button rifling does induce stress and we stress relieve and monitor how much the barrels shrinks and ever heat of steel will shrink the same if it doesn’t we have to change tooling size and get back to size and if I turn a Barrel to a number one contour muzzle of .560 od it will not open up in size to where it matters.
Hey I went to store an stocked up on popcorn and budlight.
Is heating the only way to stress relieve a barrel?
You could try running a case of Bud through it.
Usually works for my stress.
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