Found pressure signs way early.

[Obsessed]

New to rifle reloading.
As the title suggests I ran into pressure signs (flattened primers and very stuck cases) extremely early. Rifle is a .308 savage 20" barrel 1 in 10 twist. Loads are as follows:
Once fired LC and Hornady brass FL sized and trimmed to 2.005" no crimp.
175 SMK
WLR primers (second hand)
42 gr Varget (checked and rechecked)
2.800 COAL. Base to ogive 2.225. jump .020.
Chronograph was all over the place between 2400 fps and 2613 fps.
I'm looking for ideas. I suspect the primers may have been mislabeled. Would a magnum primer overpressure at only 42gr? Has anyone seen a hot batch of Varget?

Thoughts?

Thanks in advance!

 

[spife7980]

Segregate your brass and work with only one at a time for starters.

 

[Rob01]

Using two types of brass at the same time is a bad idea. Only use one or the other when working up a load.

That’s a low charge of Varget. Are you sure you are off the lands and not into them? Some Savage barrels have come through with short throats and could cause issues.

 

[Obsessed]

I'm sure it's off the lands. Lands are 2.245 from base, I loaded all of these rounds .020 off. I've been doing my loading in groups keeping brass segregated. Five LC cartridges had pressure signs. So I tried one Hornady that I loaded and got the same. 42 gr was the recommended start point so I was surprised to see pressure signs.

 

[ACard]

Research the Winchester primers as well, google the lot number and make sure they are not some of the problematic lots from years ago. Winchester primers have in general tended to cause pressure spikes for me in the past.

 

[straightshooter1]

New to rifle reloading.
As the title suggests I ran into pressure signs (flattened primers and very stuck cases) extremely early. Rifle is a .308 savage 20" barrel 1 in 10 twist. Loads are as follows:
Once fired LC and Hornady brass FL sized and trimmed to 2.005" no crimp.
175 SMK
WLR primers (second hand)
42 gr Varget (checked and rechecked)
2.800 COAL. Base to ogive 2.225. jump .020.
Chronograph was all over the place between 2400 fps and 2613 fps.
I'm looking for ideas. I suspect the primers may have been mislabeled. Would a magnum primer overpressure at only 42gr? Has anyone seen a hot batch of Varget?

Thoughts?

Thanks in advance!

What scale are you using to measure your powder charges?

What chrono are you using?

You're LC brass very likely has less volume/capacity than you're Hornady brass; enough that can result in very noticeable difference is velocity/pressure. Combine that with Winchester primers that can push pressure up some adds to the issue you appear to be having with the LC brass.

Brass with a case volume of ~55.9 grs H2O loaded as you've described should give you an MV of something around 2,520 fps out of your 20" barrel. That 42 grs of Varget in such a case puts the pressure just below the maximum of 62,000 psi at ~58,700 psi. LC brass with an assumed volume of 54.8 grs H2O puts the estimated pressure right at 62,000 psi. Hornady brass that's I've measured had a case volume of 55.5 gr H2O and should still be under that max. . . except for the questionable primer issue and yes, magnum primers can do that when you're close to max pressure for that charge weight in a .308 case.

A combination of things can be a play here, including how much variation you might have in you powder charge weight. That's why I asking about it.

Anyway, these are my thoughts.

 

[nn8734]

New to rifle reloading.
As the title suggests I ran into pressure signs (flattened primers and very stuck cases) extremely early. Rifle is a .308 savage 20" barrel 1 in 10 twist. Loads are as follows:
Once fired LC and Hornady brass FL sized and trimmed to 2.005" no crimp.
175 SMK
WLR primers (second hand)
42 gr Varget (checked and rechecked)
2.800 COAL. Base to ogive 2.225. jump .020.
Chronograph was all over the place between 2400 fps and 2613 fps.
I'm looking for ideas. I suspect the primers may have been mislabeled. Would a magnum primer overpressure at only 42gr? Has anyone seen a hot batch of Varget?

Thoughts?

Thanks in advance!

Double check your CBTO…my .308 175 smk-based loads have a CBTO of 2.160 and COAL of 2.820, jumping .030 into the lands.

Also, who told you 42g should be the starting point? Both my .308s use the same components you do (except i run Rem 9-1/2 primers) and 41.5 and 42 are my charges in my M40A5 and SR25, respectively. Both are .5 below max as determined by pressure ladders for each rifle.

 

[Obsessed]

Using an RCBS 502 and Calwell chronograph.

I have done a bunch of digging and found that while many loads would be light with 42gr my 175 SMK are over max per Sierra. There is a lot of conflicting info between manuals. I was using charge weights from a Hornady manual wrongfully thinking the 175 SMK would be similar to 178 ELD.

 

[akmike47]

I run 41.5 and 40gr and get 2560fps, good enough for 1100yds.

 

[Haney]

Double check your CBTO…my .308 175 smk-based loads have a CBTO of 2.160 and COAL of 2.820, jumping .030 into the lands.

Also, who told you 42g should be the starting point? Both my .308s use the same components you do (except i run Rem 9-1/2 primers) and 41.5 and 42 are my charges in my M40A5 and SR25, respectively. Both are .5 below max as determined by pressure ladders for each rifle.

I think Hodgdon starts their load hotter than Sierra Max load .

 

[Rob01]

Those Hodgdon numbers are what I have always used. Most of my loads with 168-178 bullets is around 44grns of Varget. Never used LC brass but used a lot of Hornady and Lapua. Never an issue. I use Fed 210 primers though and also haven’t used a factory barrel in a long time so thinking it’s got to be something between the primers and barrel/chamber in the rifle. If you can only load lighter than just do it to be safe and just find an accurate load in the lower charge.

 

[nn8734]

I use LC LR and Federal COTS brass, along with Varget in all my 308s and have always been either at or slightly under 42g with so the OP hitting pressure at 42 grains w/LC brass and WLRs strikes me as “normal” but am a little surprised he’s also getting pressure with the Hornady stuff as it should have greater case capacity and produce less pressure w/the same charge, primer etc unless he’s over with both, just one moreso than the other.

View attachment 8089337
I think Hodgdon starts their load hotter than Sierra Max load .

Yep, and with Federal brass my 308 loads im usually between 42.5-43.5ish using Varget and F210/210M.

@Obsessed - what’s your neck diameter of fired vs unfired cases?

You running a can?

Are you working with LC or LC LR brass? The latter is preferred and the former sucks for precision loading, in my experience.

 

[straightshooter1]

Using an RCBS 502 and Calwell chronograph.

I have done a bunch of digging and found that while many loads would be light with 42gr my 175 SMK are over max per Sierra. There is a lot of conflicting info between manuals. I was using charge weights from a Hornady manual wrongfully thinking the 175 SMK would be similar to 178 ELD.

As I suspected, due to the accuracy limitation of the scale and chronograph, they will contribute to the issues you're experiencing, especially when other factors are bringing you to or close to maximum pressures. If the chrono is not set up just right and the lighting is off or fluctuating, you can see large variations in velocity readings. I'm not concluding that's what's happening for you, but I've experienced and seen this on a number of occasions. While the scale has an accuracy of .1 grs (that's more like +/- .1 grs), it's not hard to be off more than that depending on how it's used; again . . . based on my own experience using such a scale (like, I'd be doing good to get ES 's from 30 - 75 fps and SD's in mid 20's and upper 30's . . . one and a while in the teens). I never really had any pressure issues as I didn't load close to max pressure, though my best load with Varget was at 41.0 grs in Federal brass with CCI primers . . . and I tended to load long rather than at 2.800 COAL (like at 2.862, having plenty of freebore to do so). These days, I use a very good scale (FX-120ki) that has been a big factor in getting my SD's down into single digits, along with other brass prep refinements, which was my goal.

Depending on your goals, they'll determine what to do and you'll figure out what works and what doesn't and what's worth the effort or not. You should be able to use the brass you have without pressure issues if you reduce the loads a little, and or use Federal primers (I know, they're almost impossible to find these days). And you should be able to get 2500 fps out of your brass with Varget without being at max pressure, with a little less powder and even with milder primers.

What you might consider is getting hold of some Winchester brass as they have much thinner case walls the LC's, which will allow you to use that amount of powder with less pressure or a little more powder with a corresponding increase in velocity without the pressure issue. This rifle reloading business, when you're starting out, is about experimenting safely to find what works for you for the level of precision you want.

. . . just more of my thoughts from past experience when starting out with precision reloading.

 

[Obsessed]

I use LC LR and Federal COTS brass, along with Varget in all my 308s and have always been either at or slightly under 42g with so the OP hitting pressure at 42 grains w/LC brass and WLRs strikes me as “normal” but am a little surprised he’s also getting pressure with the Hornady stuff as it should have greater case capacity and produce less pressure w/the same charge, primer etc unless he’s over with both, just one moreso than the other.


Yep, and with Federal brass my 308 loads im usually between 42.5-43.5ish using Varget and F210/210M.

@Obsessed - what’s your neck diameter of fired vs unfired cases?

You running a can?

Are you working with LC or LC LR brass? The latter is preferred and the former sucks for precision loading, in my experience.

I'm not running a can, just a brake. Do you want OD or I'm assuming ID on the neck?

 

[357Max]

I'm not running a can, just a brake. Do you want OD or I'm assuming ID on the neck?

OD of loaded round & OD of fired round @ neck.

 

[nn8734]

I'm not running a can, just a brake. Do you want OD or I'm assuming ID on the neck?

See @357Max response…

 

[Obsessed]

See @357Max response…

Loaded 3.038
Fired 3.045

Sorry for the delayed response, been a bit tied up for a few days

 

[Bacarrat]

What powder thrower are you using? Your ES of 213FPS is really high. Highly doubt it's a primer issue. I run almost exclusively WLR primers for years and never had a problem. If anything toss the Hornady brass. I don't care what people say, it's junk. It's soft as hell and it's not consistent at all.

 

[Obsessed]

What powder thrower are you using? Your ES of 213FPS is really high. Highly doubt it's a primer issue. I run almost exclusively WLR primers for years and never had a problem. If anything toss the Hornady brass. I don't care what people say, it's junk. It's soft as hell and it's not consistent at all.

What brass have you had the best results with?
Using a Redding thrower and hand trickling every load up to desired charge. Scale is RCBS and has been verified accurate with a friend's scale and also weights.
I have since my first post found that I may have been way to close to the chronograph, giving me bad results. I need an other range day to verify.

 

[Bacarrat]

What brass have you had the best results with?
Using a Redding thrower and hand trickling every load up to desired charge. Scale is RCBS and has been verified accurate with a friend's scale and also weights.
I have since my first post found that I may have been way to close to the chronograph, giving me bad results. I need an other range day to verify.

I only use Lapua brass but LC works just as well too.