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.308/Varget Update: OCW Pic and Input Needed

W

WB300

Cranky Yankee
Full Member
Minuteman
Jan 15, 2011
839
297
54
GA
So after reading up on .308 Win loads here, I decided to jump on the wagon. I purchased Winchester new brass, CCI BR2 primers, Varget, and Sierra 155 gr. Palmas. The brass was FL sized and run through an ultrasonic cleaner. Sierra book has max load of 44.8 gr seated at 2.775", Lyman book puts max at 48.0 seated at 2.800", and Hodgdon site puts max load at 47.0 at 2.775" I loaded rounds for an OCW test as follows: 45.0, 45.4, 45.8, 46.2, all at OAL of 2.780". Each powder charge is measured on an RCBS beam scale. Temps hear in South GA run around 90+ late mornings, so letting the barrel cool between shots takes a while. After shooting these and observing target and brass, I was going to load more rounds next weekend, below or above those to give me a better sample and avoid higher temps throughout the day. At 45.0 grains, I already had slight flattening and slight cratering of the primer. At 46.2 grains, the flattening and cratering were more pronounced to where my fingernail could easily catch the crater. I did not have any ejector marks and no sticky bolt lift. I see here where many folks find good loads between 46.5 and 48 grains. Rifle is a factory Rem 700P LTR, 20" bbl. 1-12 twist. I hear that these rifles do not have a tight chamber, and do have a long throat, so I should not see pressure signs well below max. When I loaded the 46.2 grains, I could hear slight crunching. I believe this is the powder compressing. When I shake the loaded round, I don't hear a lot of play in the powder. Should I be seeing pressure signs this early? Will seating the bullets out just a tad more, say to 2.800" or longer alleviate pressure signs? Seating longer will alleviate compressing of the powder, but will it lower pressure enough to allow 1 to 1.5 more grains of powder? My goal is accuracy first, but I would like to not run hot loads if I can avoid it. I can load rounds below 45.0 to add to the OCW test, but was trying to hit the higher sweet spot folks here seem to like. Not sure if it matters, but I'm also running a TBAC 30BA suppressor. Thanks in advance for your thoughts and/or opinions please.

Bill
 
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All of my .308 Varget loads are compressed. I use 178's and 175's however. From my understanding Varget is going to be a compressed load of varying degrees in a .308.
 
You'll need to post good hi-res pictures of the caseheads for us to give you a better, more solid opinion.

Off the cuff though, I'd say I supposed you had a Remington before I read you did.

Why?

Because Remington's almost always "crater" the primer pretty good.

Again, without pics it's impossible to say, but my suspicion is that you're good to go and not actually seeing signs of pressure, but rather an artifact of Remington's notorious loose fit between firing pin and firing pin hole.
 
Yep, don't rely on primers alone for pressure sign. I have 2 Remingtons one craters bad and one doesn't crater at all.
 
Thanks for the replies folks. Keep em coming please. I'm going to load some on the lighter side, and some (very carefully) with more powder. I will try to post pics of the primer from the low, high, and middle load. I am also going to dig out some factory match loads shot through this rifle and compare primer strikes.

Curiosity has me though... Will seating a bullet longer (with the same powder charge) create less pressure? I'm still a good bit away from the lands and the internal mag length won't allow me to touch them.

Bill
 
turbo54 said:
Not at all.

My Savage with CBI loves 47gr under a 155scenar. 2975fps

I've been higher but MV doesn't increase.
Click to expand...

With 155 Scenars, Win Brass, 210M, 2.8" OAL I have an accuracy node at 47.8 that shows no pressure signs. I tend to run 46.2 because the groups are a little tighter and the velocity is sitll more than acceptable. About 2950 vs 3050
 
Send that bolt off the gre-tan and have the firing pin bushed. Eliminates primer flow
 
Cruizer and turbo are correct. Remingtons are noted for firing pin holes being large. I was concerned with mine and had several long time match shooters look at my primers and they all said not to worry about it. If that is the only sign you see you shouldn't have a problem. However, I would stay away from 48 gr. of varg. that sounds too high even for a 155 My top load for 168 is 46.2. No way would I go to 48 on a 155! If you have a very liberal lead to the lands and seat the bullet to the point that it's about to fall out of the case you may be alright. but that's IF you have the added case capacity and only then work up carefully. You will probably experience short case life and primer pocket loosening.
 
Ejector wipe is a better indicator, that will start faint then get brighter. As the ejector wipe gets brighter the bolt handle will start getting harder to lift. Those are the signs you are a over safe limits. Till you see either I would continue.
 
I have a node with palma 155s, 210 primers, Lapua brass, and 45.2 to 45.6 grains of Varget. You should definitely be fine in Win brass.
 
I pulled out some fired brass from a dozen different factory match and hunting loads. Apparently the cratering is a byproduct of my particular Remington as described above. Every primer had the same type mark as my hand loads. I guess I never felt the need to pay attention to the primer strike on factory loads before. I will load up and proceed with caution while looking for ejector marks and sticky bolt lift. Thanks all.

On a side note now... Should I continue to load at 2.780" OAL? If I load to 2.800", will it invalidate the data from loads already shot? I understand that changing anything in the load will change the results, but will it be enough to give me a false accuracy node at 2.780" when it's really a scatter node at 2.800" ??

Bill
 
Any change at all from a given and usual load will affect the chamber pressure and velocity either plus or minus. Whether it be deep seat vs. shallow seat, resized vs. unsized, jammed bullet vs. jump. different ogive measurement. Generally, any change! Allow me to use an example with blasting explosives. If you place a stick of explosive on a rock to break the rock and just set it off you will only burn the rock. However, if you just place a bucket of thick mud on top of the explosive and set it off it will more than likely bust the rock, Why? You have slightly delayed the explosion long enough to force some of the energy downward. compaction, capacity, free space, burn rate, ease of bullet movement, different primer. They all play a part in the end result. Load consistantly. When you change, do it with thought and caution, and look for the signs of pressure. you are prudent in asking these questions!
 
I just did a work up with about the exact same components:

155gr SMK palma (2156)
redding bushing neck sized .331
2.81 coal
2.15 ogive
47.4 gr varget
Win brass once fired
fed 210m primer

Rem 700 AAC-SD 308 - 20" 1-10

My rifle ALWAYS craters the primer as you just noted. Here's a pic of my load on the left and a Fed GMM 175 case for reference. I went up to 47.8 with no pressure signs (flattened primer, ejector marks, stiff bolt) here in Arizona at around 100 degrees. I think I'm a little under the standard OCW node of 47.8 because of the heat here.

primers.jpg
 
did someone recommend the 155 s - difficult to get right , much better of with 168 or 175 start at 43.5 varget go up .5 s to 45.5 min oal 2810, you will get a load that shoots.
 
Would you suggest that I shoot the OCW loads I already shot at 2.78" OAL again seating them longer? Or should the results be close enough? If I understand OCW correctly, the powder charge is found first, then seating depth tweeks things. So the node should be there regardless of seating depth (as long as I am not going from jump to jam or vice-versa. I'd like to hear Dan Newberry's thoughts if he's listening.

Bill
 
Loads were from 45.0 to 47.0 in .4 grain increments. As I tried to load below 45.0 grains, I suffered some kind of brain fart and loaded 45.2, 44.8, and 44.4. Anyhow, I think it may have been a fortunate mistake as I believe there may be a node between 44.4 and 45.0. I'm going to load 5 rounds each in .2 grain increments in that area to fine tune. Am I interpreting this correctly? Does anyone see a different load I should focus on?

Bill

Pic added below.
 
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What hapened to 44.6gr, 46.4gr and 46.8gr? Id say 45.0-45.4gr or 46.6-47.0gr if your not getting pressure. Reload those up and try one last OCW to see what you like (since 46.8 is missing). Stop is you have pressure!
 
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WB300 said:
Finally got it!!!

Click to expand...

Im a complete noob. Im still trying to fully figure out OCW 100%


But I'd guess 45.0 is about your load... Again still a noob on OCW so this is more of a guess to test and see if I got reading it yet.
 
Is there possibly another node around 46.6 to 47.0?
 
I'd say maybe but your 46.2 seems to be a bit off from those 2. Again I'm still figuring this out too.

I still feel like 45.2 might be your one. But it does look like something is forming around your 46-47 but idk if you ha a 47.2 to confirm it would be easier for me to call out. I'm sure someone around here way better can call it for you better than I can
 
Out of curiosity, how far off the lands are you?

At your current seating depth, I'd say your OCW is around 44.8 (it's hard to tell since we need a 44.6 charge if we're to keep the same spacing as the rest of the charges) and again around 46.8 or 47.0 (also hard to tell without a 47.4 charge to see what's happening past 47.0). If you can measure velocity, then you could use that information plus how hard you want to push your brass to decide which charge range to fine tune in.

Another thing that kind of muddles up the results is shooting on different days since changes in temperature (ammo and ambient), wind, and humidity may affect your results from day to day.
 
You have a big time scatter node at 45.8 grains, which would point to an OCW at 46.4 grains. That's nearly right on the node we usually see with Winchester brass, Varget, and 155's.

Of course slight variations in lot numbers can skew this just a bit...

I'd go on and load these at 2.800", and test the area at 46.5 grains once again. Try 46.3, 46.5, and 46.7 grains.

When targets are not 100 percent conclusive, I normally look for the scatter node, add 1.5 percent to the powder charge, and suspect the OCW to be there in that area. Altering the seating depth will tighten the group, often considerably.

As others have said, late model Remingtons do tend to crater the primer dents, so I wouldn't go by that alone.

Good luck. Keep us posted. :)

Dan
 
Keep in mind, Palma bullets are designed for a Palma chamber right? So if your shooting true Palma bullets they will be shorter because their designed for the Palma chambering which have a shorter chamber than a standard .308 win. They will work yes, but you'll prolly be jumping them farther than a non Palma 155. Right? I almost bought a bunch of 155 SMK palmas but opted not because of they are a bit shorter bullet. Do I have this correct? This is how I understood it. Dan?
 
I've got to admit to never trying the Palma 155's, I've yet to exhaust an "ample" supply of regular 155 SMK's.

The BC on the Palma bullets is supposed to be around .500... so they're likely longer, looking perhaps similar to Lapua's 155 Scenars (that's a guess, based on the BC).

Dan
 
I don't know the length to the lands. My max (internal) mag length is 2.83" so I figured I'd load to where I have a little wiggle room on depth.

Dan, I will definitely take your advice and try 46.3, 46.5, 46.7 at 2.800". Should i shoot them round robin also?

And is it normal to be drawn to the 44.4 to 45.0 area like a fly to a bug zapper? I just can't help myself. lol!

Bill
 
If your powder charge is too close to another charge where the point of impact shifts, it's doubtful that you can get consistent accuracy (year in, year out) with such a charge.

I'd shoot those test charges round robin, just to sort of "acid test" the suspected OCW.
 
In a Remmy, bolt lift feel is the best pressure indicator. Like it was said already, primers will flow. They will flatten. Don't worry about it unless the primer looks melted onto the casehead. On the other hand, if you wait for the casehead to flow into the ejector hole you'll be way over pressure. Don't load that hot. Instead, feel how the bolt lifts. You'll notice two distinct sensations and a smooth transition inbetween. To me it feels like a "gulp." When you reach your pressure limit the case will cause the bolt to get sticky in that "gulp" area as you lift the bolt handle. I'm sorry but its hard to describe. I hope you get it.
 
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