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308 168gr HPBT vs 170gr L-Lockbase

Beautiful Mulberry

Beautiful Mulberry

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I finally got my hands on a magneto speed chronograph. 5 shot groups from both sets below. Not that much between velocity however the SD there was a difference. The 168s had 13.8sd while the 170 had 9.7sd
Remington 700 XCR tactical
Both loads produce 1/2” groups at 100yards.

I’m no rockchalk06 but I’m happy with these loads.

168gr sierra HPBT
Lapua brass
IMR 4064. -44gr
Primer LP Fed gold mm
OAL 2.870

170fr Lapua Lockbase FMJ
Lapua brass
IMR 4064. -44gr
Primer LP Fed gold mm
OAL 2.870


IMG_7878.jpegIMG_7879.jpeg

IMG_7877.jpegIMG_7876.jpeg
 
What's your barrel length on the 700?

Well done
 
20” barrel.
First time using a chronograph.

Something I don’t understand-
According to Lyman 46 manual I can definitely go higher in my grains. 44gr I’m slightly compressing powder and I’m getting pressure marks on primers. I tried 44.5gr primers started to flatten out so I backed it off. Why does the manual say I go up 2 more grains if I’m already getting these signs.
 
I'm surprised you got 44 grains in Lapua brass with a 168. Lapua has much less case capacity than say Winchester or Hornady. I'm at 2.854" COAL with a 168 ELD-M with 43.5 grains of 4064 in Lapua brass and I have to use a 12" drop tube and dump slowly. I still get the tiniest bit of crunch (which I like). No marks on the bullet and my CBTO is consistent. I'm getting 2670 around 60°, 2640 around 35° and 2600 at 3° out of my 20" 1:10

When it's warm and you are running Federal GMM or Hornady Match, you will get some flattening of primers. Your velocity is on par with these temps, bullet weight/barrel length and 4064 from my experience.

I've found over the years, the reloading manuals are just a reference on where to start. I work up until I get some cratering and heavy bolt lift. I've had flattened primers well below the posted book max. Are you seeing any ejector marks or experiencing heavy bolt lift? Also, unless you are pushing for a 1000 yard load, see if you get a velocity node under 2600 FPS. The .308 is a sweetheart in that even a slow 2500 FPS load will thump hard, fly true and kill anything you'd want to kill with a .308

For what it's worth, Hornady is calling for 43.1 max approx. 2600 FPS. Hodgdon is calling for 45.0 and 45.9 as a max around 2750 FPS. No way in hell you will get 45 grains into a Lapua case and seat a bullet at 2.870" much less the 2.800" they are calling for. Check to see what case they are using for the tested load. Hodgdon is using Winchester. My experience, Winchester has the highest case volume around.

Another thing to keep in mind. That posted data is probably from a 24"-26" test barrel that's 2" thick or more, unknown twist rate and unknown conditions. Did they test at 55° or 95°?
 
I am pushing the 1000 yard mark.
I find it really enjoyable. I’m just using a funnel that was my grandfathers made in Houston, TX I can’t remember brand I’ll check when home. When I pour I like to see it spin around the funnel. I am getting some slight cratering and sometimes heavy bolt lift. I am not getting and extracted marks.
When I did this load development I started at 40gr worked it up in .5 increments till I got the tightest groups at 44gr then stopped. The test case they used was Remington. I looked for some and could not find any. Only reason I went with Lapua because that’s the only thing I found at the time. Iv tested this load from snow on ground to 100f temp. All was stable.
Now on my ar308 1/10 twist it just chews the brass up no matter what load I make. It’s to the point I’m about ready to get rid of it.
 
If you are getting even the slightest heavy bolt lift, I'd stop there. You are not in danger of blowing your face off, but you will shorten your brass life very quickly. You could probably go higher than 44 and still be safe, but you will shorten the life of everything. Bolt face, brass and lugs. 43.5 in Lapua is where I could shoot at 90° and 5° and never be over pressure with this load.

According to Strelok Pro, my 20" pushing a 168 at 2650, will be super sonic at 1000 yards and then some. it's showing 1242 FPS @1000. Last time I shot this load at 1000, shot marker was pretty spot on to this data with impact velocity around 1220-1230. That's about 10.5 MILS and 375 inches of drop. It's an absolute bitch in the wind.

Let me ask you, did you run 40, 40.5 etc over a chrono? If so, what was your SD or more importantly, the ES on them?
 
As for gas gun brass, my M5 did the same. I would just use the Lapua in my bolt guns and bought a ton of Federal once fired off the hide and used it. It's damn good brass, but not a buck a piece or more like Lapua/Alpha/ADG.
 
I’ve been at the 44gr mark since 2020. I’m happy with it. No I did not chrono anything else. Yesterday is the first time Iv physically touched/ used one. Your fps is good at 1k.
Here is what SBC LIGHT app tells me.
Now previous to borrowing the chrono I went out and manually figured my dope out to 1k. I have it written down at the house that I will share when home. I wasn’t to far off. I could still hit the targets out at range however I’m hoping this will tighten everything up. IMG_7881.png
 
rockchalk06 said:
I'm surprised you got 44 grains in Lapua brass with a 168. Lapua has much less case capacity than say Winchester or Hornady. I'm at 2.854" COAL with a 168 ELD-M with 43.5 grains of 4064 in Lapua brass and I have to use a 12" drop tube and dump slowly. I still get the tiniest bit of crunch (which I like). No marks on the bullet and my CBTO is consistent. I'm getting 2670 around 60°, 2640 around 35° and 2600 at 3° out of my 20" 1:10

When it's warm and you are running Federal GMM or Hornady Match, you will get some flattening of primers. Your velocity is on par with these temps, bullet weight/barrel length and 4064 from my experience.

I've found over the years, the reloading manuals are just a reference on where to start. I work up until I get some cratering and heavy bolt lift. I've had flattened primers well below the posted book max. Are you seeing any ejector marks or experiencing heavy bolt lift? Also, unless you are pushing for a 1000 yard load, see if you get a velocity node under 2600 FPS. The .308 is a sweetheart in that even a slow 2500 FPS load will thump hard, fly true and kill anything you'd want to kill with a .308

For what it's worth, Hornady is calling for 43.1 max approx. 2600 FPS. Hodgdon is calling for 45.0 and 45.9 as a max around 2750 FPS. No way in hell you will get 45 grains into a Lapua case and seat a bullet at 2.870" much less the 2.800" they are calling for. Check to see what case they are using for the tested load. Hodgdon is using Winchester. My experience, Winchester has the highest case volume around.

Another thing to keep in mind. That posted data is probably from a 24"-26" test barrel that's 2" thick or more, unknown twist rate and unknown conditions. Did they test at 55° or 95°?
Click to expand...
When you get the “crunch” have you let the ammo sit 24 hrs and re measured to see if they stayed true or if the powder pushed the projectile out any?
 
Not unless the compressed load messes with my OAL on initial seating. For example I get some cruch at 53 grains but none at 52 and the same setting on the die seats to the exact OAL for both. I've tested this on 10 rounds of a 175 OTM with 4064 and measured each a few days apart. No change.

Now, my .360 stuff that takes some medieval wizardry to get that magic OAL, yes. Especially before I take it to the range.
 
Awesome! I was talking with someone and he mentioned this, I found it interesting. Thought I was getting your in put
 
One thing I've learned over the years was using a 12" drop tube and dumping slowly, makes most crunch or compressed loads, not really compressed anymore. I have two loads with N570 and that drop tube is a must.

If you are borderline marking up a bullet while seating, id measure a day later just for piece of mind. It's free
 
I haven’t ever heard of this before but I’m not a target shooter just a hunter. So what you guys are saying is a compressed load OAL can change over a day?
 
When your at a max load with a large powder like N570 or 4064, you are compressing the base of the bullet into the power column. Too much compression and bullets can come back out. You are talking about a really compressed load when this happens. I don't think I've ever reached that level and had decent accuracy.

That said, my most accurate loads have just the tiniest bit of crunch when seating.
 
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What’s the theory behind the drop tube? Does it just allow the powder to be placed more uniformly within the case so you can get more in it?
 
Yes sir. Maybe the "extra" gravity helps too? but yes. The drop tube will help immensely. My mentor did some black powder stuff and used a 2 foot brass or copper? tube to get his loads to pack. That's where I learned it.
 
I use the Harrells tubes and I stuff it into a cheap Hornady or RCBS funnel.
www.harrellsprecision.com

Drop Tubes for all Harrell Powder Measures

Get the most out of your Harrell's Powder Measure with these custom sized drop tubes. The following sizes are available: 1/4" ID 4" long 1/4" ID 6" long 1/4" ID 8" long 3/16" ID 4" long 3/16" ID 6"long 3/16" ID 8" long $8.00 each
www.harrellsprecision.com
 
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