Sticky bolt with medium charge?!

[domyalex]

So, after finding a good load with .308 150 grs, I decided to try out the Hornady 165gr (SPBT).

Hodgdon lists min 42, max 46C; the 42, 43 and 44 loads where all fine, but 44.4 gave me a hard to pull bolt on all 3 test rounds, with flattened primers on two of them (I know, primers usefulness is limited...).

What gives? Seems to me I'm still a long away from the max load.

With the 150gr, max load is 47C and I can load 46.7 without any pressure signs.

The 165gr were loaded to 2.800" (max is 2.810), so OAL shouldn't be the issue.

Surprised...

 

[Redhouse]

And this illustrates why we work up from minimum. Could be a slightly tight barrel, slightly out of spec bullets from an end of life cycle die (OK, I made that one up), or any number of other factors. Just shoot whatever was accurate below that.

 

[Ganderite]

Don't argue with your rifle. It is the one that counts, not the one Mr. Hodgen used.

A common problem is that powder dries out and speeds up. If you have left powder in the thrower, it can dry out.

Your next can of powder will seem "slow".

 

[coyote]

Pressure is pressure your primers are a sure sign that you are at peak levels back off on the load and it will be fine.

Bullets are not all the same and some build up more pressure reloading manuals are guidelines to let you know where to start, if it shoots good with less powder that is what the load is.

good luck and happy shooting.

 

[stubblejumper]

Nothing to be surprised at,you just discovered why you shouldn't assume that all loads listed in a loading manual,are safe in your gun.You now know that the max safe load for your gun is well below the max safe load listed in the manual.By the way,I would back off at least a full grain(perhaps even 1-1/2 grain) from the first sign of pressure,since by the time you see pressure signs,you are already considerably past the normal chamber pressure for the cartridge.As well,a load that shows no pressure signs this time of year,could very well show pressure signs in mid summer temperatures.

 

[mmattockx]

Have you chronographed this load to see what you are getting for velocity? If you are getting max load velocities with less than max load charges, just go with what your gun says is a max load and enjoy.

Mark

 

[Ganderite]

BTW, just make sure your cases don't need trimming fot length. That can cause pressure, too.

 

[bigedp51]

domyalex

Questions?

What make cartridge cases are you using, and what do the weigh.

What powder are you using

Just want to know more about the patient before a diagnosis.

(subconscious mind asked neural network if military cartridge cases were being used)

 

[domyalex]

Thanks all for your inputs!

So, I'm loading Federal brass, CCI primers, Varget and Hornady Interlocks

Brass if trimmed to Trim-to-length (2.005).

The bullets are boat-tailed, thus a bit longer than flat based (my 150gr). Once I'm in 44grs territory I can hear the bullet crunching a bit of powder when seating it, but if I shake the round I can distinctly hear the powder moving around a bit, so it shouldn't be a compressed load...

Federal cases have definitely less volume than Win/Rem, at least in my limited experience.

Unfortunately, no chrony yet