compressed load W760

[TroyMN]

.308 Winchester
I have worked with varget and had ladder testing with compressed loads. Hear the kernels breaking while seating, then even adding another .3, .6 or .9 grains more. A lot of crunching. I read posts about remeasuring to see if the bullet is pushed out over time. I remeasured days later and no change. When originally seating the compressed loads came out .002 or so longer than the non compressed. That is my knowledge.

This is my question. Reloading for my uncle and he has the load data to duplicate.

The powder comes up to the neck junction. This long 190 grain boat tail looks to be pushed into the powder about .350" that seems like a whole lot. I hear no crunching it is ball/ spherical vs. the kernel.

Is this any thing to be concerned about. I do not want him to have a 100 rounds of bad ammo. FYI his accuracy requirements are in the 2 MOA range. I am still using the same techniques I use to get my .5 MOA ammo. Minus the pocket uniform and flash hole de-burring.

 

[jonbearman]

The latest Hornady manual says 37.4-47.2 as the later is the hottest load they currently list. You cant expect ww760 to be the same as it was in 1981.I would back off about 3 grains and start over if I was you.Actually it probably isnt the best powder for the application.Do your homework and if you dont have a new manual ,buy one.It isnt worth you getting hurt or ruining a good rifle with over pressure loads.

 

[savagedasher]

I played some with Quick load I see he had crossed off the seating depth. If it is 2.950 it is a perfect load. Good Shooting Larry

 

[finnaddict]

The current Lyman manual shows 47.2 GRS of w760 as a compressed load at a depth of 2.775. Your depth is a bit longer than recommended but I would suggest backing off the charge as stated above and also back the bullet out more to maybe 3.000 or more. It would be good to know what measurements you have to the lands so you don't jam bullets into the chamber and leads.Ww

 

[savagedasher]

At 2.750 48.0 of 760 is 110.5 %full 67957 psi 2.950 48.0 is 101.9 % 55525 psi this was all done at 56 gr of water.I just checked one Winchester brass it held 56.9 gr Using 56.9 it is 106.9% 62314 psi on 62000 psi case. Good Shooting Larry

 

[TroyMN]

Yes I also had recommendations for my uncle for reloads in his rifle. Bring it to MN and we can work on it to get a GOOD shooting load. Besides checking the basics on the rifle. I would do a couple ladder test with "HUNTING" bullets. I could use my Chorny check the normal pressure signs, maybe get a round that will feed through the magazine that likes to jumped.
I had SUGGESTIONs... I am not a great hunter but I do not think a Match hpbt bullet is a good round for hunting bear.
I can not control anyone but myself. HE made the decision to stay with the load he has been shooting and was happy with, if its not broke don't fit it.
My post was to see if anyone knew any major changes in the components. Examples, Federal cases decrease volumes back in 94, or Hodgon reformulated the Win760 when the two merged....

None of us really know enough to make assumptions regarding the pressures in his rifle with his load, including me. My 20" barrel SPS uses larger than listed max powder charges, however I would not use that round in someone else's 30" palma rifle.
A couple facts that I can add would be the fired cases with this load data have slightly flatten primers with no ejector marks. The load was set to 2.800 COAL however it would not feed via magazine, thus the crossed off and changed to 2.750 COAL.

Yes I have out dated reloading manuals. That is why I try to use the most current loading data from the manufactures websites online.
This is what I read on Hodgons
Cartridge: 308 Winchester
Load Type: Rifle
Starting Loads

Maximum Loads

Bullet Weight (Gr.) Manufacturer Powder Bullet Diam. C.O.L. Grs. Vel. (ft/s) Pressure Grs. Vel. (ft/s) Pressure

155 GR. SIE HPBT Winchester 760 .308" 2.775" 48.0 2625 40,500 CUP 51.0 2793 50,200 CUP
165 GR. HDY SP Winchester 760 .308" 2.750" 48.0 2537 43,500 CUP 52.0 2704 49,200 CUP
175 GR. SIE HPBT Winchester 760 .308" 2.800" 46.0 2484 40,300 CUP 49.0 2629 50,100 CUP
180 GR. SPR SP Winchester 760 .308" 2.800" 46.0 2433 39,800 CUP 49.0 2573 47,500 CUP
190 GR. HDY BTSP Winchester 760 .308" 2.740" 45.0 2386 42,100 CUP 48.0 2504 48,700 CUP
200 GR. SFT SP Winchester 760 .308" 2.700" 45.7 2430 46,500 CUP

When first looking at this 48.0 grains being max charge. It even seemed on the low pressure side 48,700 CUP.
I am choosing to duplicate his current load, I am not choosing to be neglectful about it.

Back to my question, compressed loads with W760 power. There is a point where powder compression will cause bullet to push back out, case deformation or possible poor ignition. Compressing W760 in a 308 case .350" which if any is that likely to cause? Any personal experiences?
Thanks
Troy

 

[TroyMN]

Found the reason for the old load data working. The Federal brass weight of the old has an average of 168.54, the newer federal brass weight average is 182.00. The case lengths are within .003, so some where there is less brass causing more internal case capacity (I did not check neck thickness)
I loaded a old case with the 48.0 grains and it made slight bullet seating ring mark.

There is a point where powder compression will cause bullet to push back out, case deformation or possible poor ignition. Compressing W760 in a 308 case .350" which if any is that likely to cause? Any personal experiences?

Option #4 compressing .308 diameter bullet .350" into a 308 Winchester case will cause bullet deformation. You can feel the indentation caused but bullet seater.
So my conclusion is the OLD previous load was on the edge of being too much powder in the case for that bullet and seating depth. With the new federal brass it is not even close.
I will not be duplicating that load with the newer federal brass.


I have this problem of needing to understand WHY something will or will not work.
Everyone, Thank you for your feedback sorry if my response seemed rude or aggressive. It just seemed my main question regarding the compression of W760 was not being addressed.