Did you pick up any accuracy?

In my experience, the 175SMK is so jump-tolerant, that it rarely makes a perceptible difference. Are you saying you cut a NEW barrel chamber to your specs, or set back your old one?

 

Brand new Barrel. Dropped off the old barrel/action at Benchmark and told them to call me when it was trued with a new 24" 5-C barrel on it. Was easy as they are located only three Freeway exits from me. The only "set back" was to my wallet


They used a "no-turn" match reamer which gives me minimal clearance on a new case at the neck, a nice tight freebore (.3085") and minimal throating.

Accuracy is superb. The profile is supposed to be a #7 but not sure "who's" #7. Heavier at the breech end than the old 5-R milspec but still has the same muzzle dia. First shot is as accurate (even cold bore) as the 50th shot.

 

Remington Model 700 AAC

Hornady 178 A-Max
43gr Varget
Federal 210 Match Primers

 

Found a good supply of IMR 8208 XBR so I decided to work up a load for my 175 gr SMK's I like to have a few "recipes" so I can use whatever happens to be available.

The load:

175 gr SMK
Lapua 3-4 X fired brass, annealed, trimmed, and F/L sized Total indicated runout on case necks <.001".
Federal GMM primer
42.2 Gr IMR 8208 XBR

Estimated Speed ~2630 fps (Will chronograph next time at range)

The Rifle:
Remington 700 that started life as a 5-R Milspec (with Stainless Steel Action)
Benchmark 24" 5-C Barrel chambered with "No Turn" Match Reamer
Bell and Carlson Medalist Varmint/Tactical Stock
Sinclair Tactical Bipod
NightForce 12-42X56 NXS Scope
Birdshot bag filled partially with sand for rear bag.

The results:

This was shot at 200 yards on a morning with fog coming and going. At times the other shooters had to stand down as they couldn't even see their 300 yard targets. I was able to just make out the orange circle and had to wait for the dot in the center to appear before pulling the trigger. The last shot was the one at the right which I fired just as the target disappeared from the scope, totally.

This was part of a workup. 5 shots per load in .3 gr increments. Started at 41 gr and was totally discouraged as the test progressed. All of a sudden, this group popped up and it's only .2 gr below published max. Rest were OK for knocking down game inside of 300 yards but not good enough for me.

Using "On Target", the 4 shot group measures a max spread of .224 MOA with an Average To Center measurement of .101 MOA. Actual measurement of the group was .469" and again, shot at 200 Yards.

When I add the 5th shot the group opens up to .457 MOA but the Average to Center remains lower at .152 MOA.

Considering that this was shot in the fog I'm good with this and am going to keep this load. Considering the "temperature resistance" of the 8208 XBR it may well be my "Winter Load". Who knows, if it keeps shooting like this for me I may even stop using Varget (like I could even buy more if I wanted to right now)

BTW, the "42 & 42.4" notes are what I'm going to use to verify this load. May even get smaller with just a little more, or just a little less.

 

I'm loading 175 SMKs over 41.8 grains of 4064 Lapua brass 210 fed primers.
Remington 700 police 26" 1 in 12

At 100 yards.

At 300 yards.

 

I'm loading 175 SMKs over 41.8 grains of 4064 Lapua brass 210 fed primers.
Remington 700 police 26" 1 in 12

At 100 yards.
View attachment 2142

At 300 yards.

View attachment 2143

Jut a suggestion based both on advice given me by an experienced (and winning) BR shooter, and my own experience. When a group is vertically strung like the top one (which is still a nice group), try a little more powder. The person offering the advice to me had a standard rule-- "Vertical? Add more powder. Keep going until it squeezes into a triangle or single hole."

My personal experience with same components that you used puts my loads in the low to mid 40's.

 

This is follow up to post #20, using IMR 4064 powder,175gr SMK, WLRP’s and once fired FGMM brass. The major difference between this test and the test on #20 was that the OAL was stretched out to 2.880”. This length was chosen because this length will still function in my AICS magazines. Foggy morning.

 

Thanks to everyone . This is a great thread. I was able to finally et some testing time. The group was fired from a mat with my left arm as support. a little over 100 yards. very satisfied with the first results. This was fired with my pre 1980 Savage 110S. the rifle has been bedded, and has a floating barrel.

 

Great shooting Mike and Dan!

 

175 MK
IMR 4064 @ 41.8
Fed 210m
FC Match Brass
excellent load duplicated Fed GMM load

 

Is there a reason why 175gr bullets seem to be the most popular in here? Are they just easier to come by, or is it all personal preference?

 

Because they just work so damn well.

 

Better BC than the 168

the 185 is the heaviest I would shoot in the 7.62

the 300 Win the 190 to 220 MK come into play

 

This was part of a workup. 5 shots per load in .3 gr increments. Started at 41 gr and was totally discouraged as the test progressed. All of a sudden, this group popped up and it's only .2 gr below published max. Rest were OK for knocking down game inside of 300 yards but not good enough for me.

Just curious, deadshot, since I just got some xbr8208. Your text says you used 0.3 grain increments in your load workup but you included 42.4. That doesn't fit in the progression from 41 - was that a typo or do you vary your increments?

 

As I got closer to the max I varied the loads slightly trying to sneak up on max rather than having it slap me in the face. I "split the difference" between 42.2 and 42.6. I follow the advice of an old BR shooter that always says "if you have vertical dispersion, add more powder". That's what I was doing but was coming up against the "max" (at least for me).

 

It's not just the better BC that comes into play. It has to do with the overall bullet design. The 168's tend to destabilize sooner, making them less predictable as you approach 1000yds in the lower elevations. The 175's do not exhibit these problems.

 

Does this destabilization also apply to the Berger 168 Target Hybrid? It has a higher BC and a design that differs from the more common SMK 168.

 

Apparently Berger uses G7 values for its bullets to compensate for deficiencies regarding shape in the older G1 standards - at least if I understand their press releases correctly. So I guess I should compare the G7 values of the SMK 168 & 175 to that of the Berger 168 Hybrid to answer my own question?

 

You want to avoid confusing a bunch of bullet variables. Ballistic Coefficient (BC) is a measure of a bullets wind resistance, essentially. On the other side of the equation is the ability of a bullet to remain stable over a long distance. This is more a function of velocity, barrel twist, and bullet length. What Brian Litz has done is to boil this last part down into a "Form Factor" that gives a pretty good idea how well a bullet will maintain stability. The BC's are again, more of an aerodynamic measure.

 

G7's
168 SMK - .218
175 SMK - .243
168 Berger Hybrid - .266

 

Trying the OCW method with 175 SMK and 4064. The system seems to overlook the lighter charges. Anyone notice this?
Here's my loads
Sighters - 41.4, 42.3, 43.1 (all x 1)
Loads - 43.1, 43.5, 43.9, 44.3, 44.7, 45.1, 45.5, 45.9 (all x 3)
Looks like 44.0 to 45.0 will need close look flattest velocities (2748 to 2800)

All within 1/4" vertical

 

I've found that the most consistent loads were in the 42-43.5 gr range with the 175 SMK. 43.2 gr yielded an SD of 8.2 fps, a Mean Absolute Deviation or 6.1 fps, and speeds averaging 2650-2660. Groups of 3/4" at 300 yards sure were pretty.

Heavier loads just gave higher spreads in velocity, higher pressures, and accuracy fell off.

For Go Fast loads with the 175 SMK I use IMR=8208 XBR. 42.2 gr in a Lapua Case, lit with a Fed GMM210M primer gives me an average of 2704 fps with SD 8.6 and MAD 6.3 fps. Again, accuracy at 300 yards is ~1/4 MOA. No pressure signs at that load combination.

I don't chase the fastest speeds, just the most accurate ones that will get my bullet to the target at 1K.

 

To clarify. That's 1/4" vertical spread for group centers of 44.3 to 45.1.

 

Well lost a long post somewhere into cyberspace, so now you get the short abrievated post. I am looking for a new load using Lapua brass, IMR4064 Powder, CCI BR2 Primer and 175 SMK. I shot 10 round groups varying .3 grains starting at 41.7 up through 43.5, however, I saw some pressure signs at 42.3 and stopped. I pulled the remaining rounds apart and loaded them in groups .1 grains apart, starting at 41.7 and ending at 42 grains. The results of the second test are below. I was looking for the smallest vertical dispersion, but the differences are so small I can attribute it to my shooting skills or lack there of. 42 grains performed well in both tests, performing slightly better on the first day. I realize using the pulled cases for the second test could introduce a variable of different neck tension, but I thought as they all were pulled with the same process, an inertia bullet puller the results would still be valid, as I am looking for the powder charge not neck tension. The seating depth was the same. The 41.8 seemed to have the best looking group, but it also had the highest vertical dispersion. I am hesitant to just load 42 grains as I found pressure signs at 42.3 and I was shooting on a cold day (36 degrees). I want a load I can shoot in the summer as well and am not sure how temperature sensitive IMR4064 is. Any suggestions or comments would be appreciated.

 

41.7 up through 43.5, however, I saw some pressure signs at 42.3 and stopped.

What did you see as "pressure signs"? Flat primers? Craters at the firing pin strike? Ejector marks? Hard bolt lift?

I find that the 42.3 gr load is nowhere near a high pressure load in my rifle, even with a match chamber. I DO find a lot of flattened BR-2 primers however. If you have no ejector marks, excessive cratering (ignore the false crater caused by a Remington factory bolt with chamfer on firing pin hole), or stiff bolt opening, you're just seeing normal primer material flow. If you truly had high pressures the primer metal would look like you poured liquid metal in the primer pocket and the demarcation line would be almost non existent. It would look like a knife edge made the line.

A .308 Win case (Winchester brand) can take up to 45.6gr under a 175 gr Sierra SMK and still be well below the max SAAMI pressure of 62,000 PSI for the cartridge.

Your load of 42.3 is well below that max and again, if only the primer is showing "Pressure Sign", don't discard that load. I'll be shooting more of that exact load tomorrow and I find it to be only a "Mid-Load" for my rifle. Another accuracy node showed up just over 44 grains.

Many a good load has been pulled just because a primer got a little flat. Change to a Tula and you'd probably think you had a "powder puff load"

 

I had a pretty stiff bolt lift on all ten of the 42.3 loads and very slight ejector marks. The primers looked good. I wasn't worried it would be unsafe, I just didn't see the point of going further as it was 28 degrees on the day I shot the first group. My chamber is pretty tight on this rifle. The barrel is a Bartlien tight bore ".299", 5R grooves and an 11.25 twist. I have no doubt a heavier load is safe in someone else's rifle, but I don't need the speed in mine. I have a .300WM for that. I will run the loads through my chronograph this week. I am only looking for 2600-2650 fps. I think I am pretty close to that as my 200 yard zero is the same as my last load using 43 grains of RL15. I could have used some Federal match primers, but grabbed the CCI off my shelf instead and promptly primed 500 cases, so this batch will be using CCI, I will try the Federal next.

 

Something else to consider when you have no pressure signs on the primer, yet ejector marks appear, is the headspace. Not necessarily the headspace created by the bolt to chamber but the case itself when you size it. Using .308 as an example, if the "Go" headspace gauge is nice and snug at 1.630" but a sized case measures 1.622", the case head will slam against the bolt face and leave an ejector mark. You'll also start noticing head separation grooves inside the case. Ideally, the case is sized so the measurement from case head to the datum point (where the shoulder measures .400" in dia) should be around 1.628"-1.6285". The bolt should require a very slight effort to close in order to keep the brass from "banging" the bolt face. In practice a lot of people just follow the sizing die instructions screw the die down tight to the shell holder.

Use a Hornady Headspace gauge and measure the headspace on a fired case and then adjust the die until it "bumps" the shoulder back about .002" and it's very possible that the ejector marks may go away.

If you're already measuring your cases and have set the die up as I described then consider this post just some information for those that don't and are experiencing similar problems.

As for the 28 degrees, that's what it's supposed to be when I get to the range in a few hours. To cold for just a pair of jeans and a jacket but not cold enough to climb into the insulated camo's. I hate "in-between" weather.

 

I disagree with that assessment of undersized brass causing ejector wipe.

In almost every instance, the case is held against the bolt face by the extractor. Secondly, slamming something against something else does not arbitrarily mean it will flow into the openings of the object being hit. Case head separation is due to the brass moving forward of that juncture and being thinned out during resizing/trimming, not the case head moving backwards. Take the bolt out of your rifle, and click a round in behind the extractor. In most cases, it will be quite snug against the bolt face.

While I disagree with your assessment of why ejector wipe happens, I do agree that a properly sized case is a good thing. However, not so snug that you feel resistance when closing the bolt. That is much too tight of a tolerance for a field rifle.

The number one causes of premature ejector wipe are lube left on the cases after tumbling/sizing or cleaning fluid left in the chamber after barrel cleaning. If the case is not able to grab the chamber wall as was designed, then excess pressure will be put on the bolt face.

 

I appreciate the comments. I am not sure as to the cause of the pressure signs, but am comfortable stopping at them. I do measure the shoulder to ensure proper setback and I clean my cases with untreated crushed walnut shells then wipe them down with a cloth while I make sure all the primer pockets and flash holes are free from any debris. The loaded cartridges load smooth as butter. The "sticky bolt" I described is not hard to open but takes noticeably more effort at 42.3 grains than it did at 42 grains which was minimal. I looked over the brass for a better look at the ejector swipe. It was so minor I couldn't find it, but did notice it just after I shot. Maybe it was my imagination after feel the increase in resistance when I opened the bolt after firing the shot

I don't need the bullet to go faster as I am just trying to find a load as accurate as possible that tracks close to the M118 BDC on my Leupold M3 Ultra scope. I think it was more surprised that there was not more difference in vertical height between the powder charges I did use. I still have some of my old load I will have to compare the two when I go out next. I appreciate both your input.

 

Reloading beginner here and I have a few questions and seek some wisdom. I am reloading for a .308. I am using the following components.
bullet Sierra match king 168 & 175
brass Lapua
Primer federal 210
Powder IMR 4064
I have just started with the 168. How many shots do you use to determine the load / group? If you have similar results with two different loads how would you tweak? I.E. I shot a 3 shot group with 43gr which produced 2 in one hole other a little high left. Then at 44gr same result. What would you do to try and refine load. I am trying to load to federal GMM standards so if someone has the key please advise. I have read thoroughly this thread and the loading sniper grade ammo thread. It seems powder quantity was different but close to 43gr with OAL 2.800. These where the first loads I have done, 42gr, 42.5gr, 43gr, 43.5 gr, 44gr, 44.5gr, 45gr. Please explain so a novice could understand. Thanking you in advance for some wisdom.

 

I just pulled one round of Federal Gold Match apart. The powder weighed 41.7 grains and looked exactly like IMR 4064. That is supposed to be the load they are using, loaded in their Federal brass, with a Federal 210 primer and 175 SMK. I don't know how different the case capacity between Federal and Lapua are as I didn't get around to measuring it. I have read it may take a little more powder in a Lapua case. I started at the 41.7 grains and worked up. I probably should have used Federal 210 primers as has been mentioned. I just wanted to see what load my rifle shot better. I will probably use 42 grains in my Lapua brass, but wanted to go out and do a little more testing to be sure. I think iam going to need to shoot a little further than 200 yards to see any real differences or break out my chronograph, as I could attribute the differences in my previous tests to the shooter. YRMV

 

I think iam going to need to shoot a little further than 200 yards to see any real differences or break out my chronograph, as I could attribute the differences in my previous tests to the shooter. YRMV

Both great ideas. It's hard to evaluate a load when the difference in one group to the next is small. Open up the range to 200, or even 300 yards and the differences in groups will be a lot more graphic. A one inch group at 100 yards opens up to 3 inches at 300 yards but a 1/2" group, only 1-1/2". Kind of like looking at things through a magnifying glass. Only downside is that there's a longer walk out to the 300 yard target line.

For those who are trying to dupe a load so their BDC is accurate, a chronograph is the only way to do so without wasting a lot of ammo. ALSO, everyone should take some time to read the attached document. Try using the BC's that were measured by Brian Litz rather than those published by the bullet Mfr's. Some are grossly overestimated and some under.

http://www.dtic.mil/dtic/tr/fulltext/u2/a554683.pdf

 

Remington 700 SPS Varmint, 26". Vektor muzzlebrake, Leupold 15 MOA base, Rechtnagel rings, SuB PM II FFP and B&C Varmint stock. No work other than threading of barrell done.

175 SMK. Lapua brass. CCI200, 42,4 grains of Vithavouri N-150. About 780 m/s (2560 fps). My best ten shot group at 500 meters (548 yards) is 93 mm. (3,661 inches). Dont have the slightest clue what that is in MOA.

This is as safe as loads can get, still a few grains from being close to Lapuas own "max load". Havent needed more velocity, and I have shot at steel up to 950 meters (1038 yards) with consecutive hits, 27 of 30 rounds if I recall.

 

42.0 to 42.5 grns varget, 168 berger vld hunting, nosler brass, wlr primers gives me .313 to .342 groups