308 F T/R Question

[Longshooter70]

I'm expecting my rifle back from the smith any time this week. He blueprinted the action and hung a new 30" Rock Creek 1 in 11 on it.
My old load in my factory 700P was Lapua Brass, CCI 200 Primers, 43.8gr Varget with the Berger 185 LRBT loaded .010 off the lands. My velocity was a whopping 2590 fps. It shot well to 1K and performed as well as I could ask.
I'm going to do a full load work up but my time is very short. The TN state F Class matches are on the 1st and 2nd of next month and I need to get this thing ready. I'm just curious if this load should be close in this new barrel? I'm wondering what loads other are shooting with this same bullet just to see if I may be in the same ball park.
Any suggestions are welcome. Thanks in advance.

John

 

[jbpmidas]

I'm using 43.0 Varget with 185 Hybrids, but my velocity is 2660. I think if you stay in 43-44.0 range, you should be close.

Good Luck! You don't have much time for break-in and load development.

 

[Keith Glasscock]

43.8 should be real close. You might find that you have to go up with the longer barrel...

 

[Leaddog]

I disagree. Start low, like 40.5 and work up. My best load is 41.5 (2585 fps at 50 degrees). Walt Berger says 41.6 is max. Granted, both my rifles are tight bores with a shorter throat, but work up. Change to the Federal 210M primers for better ignition and lower ES.

I've been shooting the Berger 185 LRBT's for the past two years in a 28" Hart barrel.

Be safe, work up. Your safety is more important than a big match.

 

[dreever]

43.3 with the 185 LRBT in Lapua brass ignited by a cci 250 gives me 2615 fps in a 24 inch Bartlein.

 

[Longshooter70]

I appreciate everyone's input very much.
Mr. Watson, I've competed in many 1K F T/R matches this past year and I've had good luck at running the 185's at 2590 but the one thing I've noticed is that the ones on the leader board that are running the 185's are running them at 2700+ fps. In my mind, correct me if I'm wrong, if I can develop a safe load that will run them at that speed, it'll definitely help cut the wind. I'll be able to take better advantage of the high BC that bullet offers. If my load works out to be in the same ball park and I was getting 2590 from a 26" factory barrel, the extra 4" of barrel should elevate that ~ 100fps. One thing I do know is the 185 LRBT has the same bearing surface length of a 168 SMK. I think that's why people are able to use a little more powder and drive them a little harder, safely.
Blueprinting my action and putting a premium barrel on plus developing a good load should afford me a little more accuracy and speed. In my opinion, a 308 needs all the help it can get shooting at 1K.
Again, I appreciate everyone's input and welcome any feedback anyone has to offer. Thanks.

John

 

[Leaddog]

John- The difference in wind correction for a MV of 2600 v. 2700 at 1000 yards is about 1/2 inch for a full value wind change of 1 mph. In a 5 mph pickup or let off that is 2 1/2 inches. In a perfect world, you would go from the center of the X ring to the edge of the X ring. That's a big change and most experienced shooters would see that happening through wind/mirage observations. So, it's not necessarily the 2700+ MV guys shooting the higher scores, but those that are better at reading conditions.

There is one important caveat and Laurie H has explained it previously. It is the transonic zone. This is where a bullet starts to lose some stability although still faster than Mach. At 70 degrees, the 2600 MV is still running at 1280 fps while the 2700 MV is at 1350. Since Mach is about 1130 fps at 70 degrees, both are still well above. 2700 does have a slight advantage. Those running the 185's above 2800 (a few shooters with long barrels do) arrive at 1000 at more than 1400 fps+. Clearly desirable, but a real barrel burner.

In my opinion, skill and experience and knowing what your rifle and ammo shoots, trumps extra speed many times.

 

[MrMajestic]

Your seating depth/COL will have much to do with what it takes to get what velocity. Looks like 3" and maybe a little more will leave you with a 1/2 caliber of bullet shank(sans boattail) left in the neck which will help your cause to safely get where you want to be.

 

[mattt]

When I got my Bartlien 32" 308 back from them I loaded some 42 grain and won my first match.Well for the next couple months I played with loads and lost matches. Now I am back at 42 varget 185 berger bt.Last weekend did load testing at 1K and 42 grains had best vertical.

 

[Esmith]

Several of the guys I've seen shooting the 185 lrbt are pushing them at 2800+ as well. They are doing well. Better then me anyway. I'm still shooting the 175 smk. One of them recommended to me the other day to speed the 175 up. Currently I'm using 43.3g of varget at 2700. I've tested up to 47.5g of varget at 2915 fps with no pressure signs. What are you seeing out of the 175 SMK?

 

[Longshooter70]

Thanks again all for your posts. It's really appreciated.
Mr. Wilson, I guess what I'm saying is that I hope with the action being blueprinted and having a premium barrel, I hope my accuracy increase will be a lot greater than shooting a factory 700 P with a 26" barrel. The extra speed gained from the extra 4" of barrel is gravy. I compete with this rifle in places barely above sea level to about 1200 ft asl not counting density altitude. I like to keep the bullet over 1.2 mach in all places. The load I worked up and have been shooting was worked up by using the OCW method. It is in a good midrange node. Not driving the bullet as hard as I could yet yielding the speed I needed to compete in all the venues I shoot. I'm hoping the same load(albeit with a little fine tuning) will afford me the same luxury with a little extra speed. I pick the rifle up Saturday and will measure the throat to find how long I can seat my bullets. My plan is to load up a few of the same load with the adjusted seating depth and try them while I'm breaking the barrel in. If they shoot the way I hope they will I'll be in the cat birds seat. If not, I will perform a complete OCW work up and find a load that will accomplish what I'm looking for. I, like you, had rather have a slow accurate hit than a screaming fast miss any day. Accuracy always trumps speed as long as there is enough speed to get the bullet to the target at 1.2 mach and above. I appreciate your time and your perspective. Good shooting!

John

 

[Leaddog]

Accuracy always trumps speed as long as there is enough speed to get the bullet to the target at 1.2 mach and above.
John

Don't get too hung up on the Mach 1.2 issue. The 185 LRBT's handle the transonic zone quite well. Spend your time finding a load that produces the least amount of vertical at 1000 yards and you'll have your load. That may be at, above, or a bit below Mach 1.2. Good shooting.

 

[Turbulent Turtle]

My experiences with the .308 in F-T/R have been substantially different than Charlie Watson’s. First of all I get my loading information from a reliable source, the powder manufacturer. For 180/185 gr bullets, Hodgdon’s website lists Varget with a starting load of 41.0 gr for 41,200 CUP and a max load of 45.0 gr for 49,600 CUP. The velocities listed are not important to be because they are in 24 inch barrels and I have a 32 inch barrel on my rifles. Just for the record though, I get an increase of about 200FPS over the Hodgdon velocities.

My optimum load is just under Hodgdon’s max and I get velocities above 2800FPS out of my long barrels. I’ve shot the 185 Berger with that load but I have gone back to my first choice bullet, a 180gr JLKLBT and have remained there since, and with virtually the same load.

I would certainly not describe this load as a “barrel-burner,” as I have one Broughton barrel that has 3358 rounds through it and it was still good enough for scores in the 190s with one of them having 5 Xs in a row back in June of this year. That does not sound like a “burnt-out” barrel to me. Also Lapua brass has up to 8 loadings in it and the primer pockets, while looser than in virgin brass, still present some resistance when seating primers and are just fine. I attribute this to a tight chamber and the constant use of a small base, full length resizing die; I have all 500 original cases and they are still in the rotation.

The difference in wind correction between 2600 and 2800 is an inch per wind MPH, and with some of the winds we get here, anything helps.

And while “skill and experience and knowing what your rifle and ammo shoots, trumps extra speed many times”; skill, experience and so forth ALONG with extra speed makes for a formidable combination.

 

[AR15DCM]

I always did better with Reloader 15 than Varget. Here is my load data if interested. (attached)