OCW Help. First Reload. 175 SMK HPBT .308

[ctcash]

This is my first reload(and first post) and I chose the OCW load determination to see what works. I am shooting a M40A5 with Remington 700 short action and a 25" schneider barrel(1 in 12). I loaded in increments of .3 from 40.8 to 43.5. These were the recommended min and max. The load is federal brass, with Fed 210M primers, 175g SMK HPBT and IMR 4064. COAL was 2.800". Run out for each was <0.001" and was verified with a Hornady concentricity gauge. All brass was once fired.

Avg. Velocities, Std Dev
1. 40.8 - 2618, 9.63
2. 41.1 - 2628, 9.88
3. 41.4 - 2636, 12.36
4. 41.7 - 2653, 13.59
5. 42.0 - 2674, 6.65
6. 42.3 - 2695, 12.19
7. 42.6 - 2700, 14.38
8. 42.9 - 2728, 5.1
9. 43.2 - 2733, 8.38
10.43.5 - 2753, 7.85

I took 3 shots with each weight shooting round robin with 5 minutes between each shot. The temperature was 90°F. There were no pressure signs even at the 43.5 so I may go higher. Being new to this, I am curious as to which string of loads appears to be the best out the 10? 43.5 has the tightest group. But they all appear to be in the same direction from center, with 40.8 being an exception. What are your opinions? Thanks for your time!

 

[straightshooter1]

This is my first reload(and first post) and I chose the OCW load determination to see what works. I am shooting a M40A5 with Remington 700 short action and a 25" schneider barrel(1 in 12). I loaded in increments of .3 from 40.8 to 43.5. These were the recommended min and max. The load is federal brass, with Fed 210M primers, 175g SMK HPBT and IMR 4064. COAL was 2.800". Run out for each was <0.001" and was verified with a Hornady concentricity gauge. All brass was once fired.

Avg. Velocities, Std Dev
1. 40.8 - 2618, 9.63
2. 41.1 - 2628, 9.88
3. 41.4 - 2636, 12.36
4. 41.7 - 2653, 13.59
5. 42.0 - 2674, 6.65
6. 42.3 - 2695, 12.19
7. 42.6 - 2700, 14.38
8. 42.9 - 2728, 5.1
9. 43.2 - 2733, 8.38
10.43.5 - 2753, 7.85

I took 3 shots with each weight shooting round robin with 5 minutes between each shot. The temperature was 90°F. There were no pressure signs even at the 43.5 so I may go higher. Being new to this, I am curious as to which string of loads appears to be the best out the 10? 43.5 has the tightest group. But they all appear to be in the same direction from center, with 40.8 being an exception. What are your opinions? Thanks for your time!

View attachment 7393012

I've run 175 SMK's in Fed Brass with 43.9 of 4064 (@ 92°F) and had some pressure signs, and . . . I had them seated .069 longer. They didn't group so well in my gun. At 43.6 grs seated at 2.916 and 81°F, they did quite well though still pretty hot.

When I run your numbers through my QuickLoad app, your MV's are very close to what the app predicts. With the 43.5 grs of 4064 with temp @ 90°F the app is showing the case is filled 104.4% of capacity (you probably have a bit of a compressed load) and a pressure just above 66,000 psi (SAAMI max is 62,000 psi).

So, based on my experience and what the QL app is showing, I think it's a good idea stay away from those hotter loads and look at the lower charges. 42.5 worked well for me (again, I tend to load long as that's what my gun likes). The 42.0 - 42.3 is what I'd suggest you test again (maybe with some 5 shot groups to verify) and play with seating depths to help tighten up those groups there.

 

[stello1001]

Why were you getting MV and what did you use to get MV of those loads?

 

[ctcash]

I've run 175 SMK's in Fed Brass with 43.9 of 4064 (@ 92°F) and had some pressure signs, and . . . I had them seated .069 longer. They didn't group so well in my gun. At 43.6 grs seated at 2.916 and 81°F, they did quite well though still pretty hot.

When I run your numbers through my QuickLoad app, your MV's are very close to what the app predicts. With the 43.5 grs of 4064 with temp @ 90°F the app is showing the case is filled 104.4% of capacity (you probably have a bit of a compressed load) and a pressure just above 66,000 psi (SAAMI max is 62,000 psi).

So, based on my experience and what the QL app is showing, I think it's a good idea stay away from those hotter loads and look at the lower charges. 42.5 worked well for me (again, I tend to load long as that's what my gun likes). The 42.0 - 42.3 is what I'd suggest you test again (maybe with some 5 shot groups to verify) and play with seating depths to help tighten up those groups there.

I plan on reloading and heading back out on Monday or Tuesday. I will try the 42.0 - 42.3 as you suggested and report back. I really appreciate it. I will have to download Quickload.

 

[ctcash]

Why were you getting MV and what did you use to get MV of those loads?

I was using the Magnetospeed V3. I'm looking at MV to familiarize myself with the overall process and build a baseline. Is MV not so important at this stage?

 

[straightshooter1]

I was using the Magnetospeed V3. I'm looking at MV to familiarize myself with the overall process and build a baseline. Is MV not so important at this stage?

When doing an OCW, it works best if you don't have anything attached to the barrel like a MagnetoSpeed (BTW, I uses one too). Maybe you've used an attachment device where it's not on the barrel??? I do OCW without the MS to be sure I'm getting the best reading on paper as something attached to the barrel can throw groups off. Like on my 24" Krieger barrel, I get groups with the MS comparable to groups without it, though still not quite the same. While group sizes are close to the same for me, my POI is shifted 12 o'clock by ~ 2.5". So, I'll shoot my OCW without my MS, then later, when I've pretty much determined that I've found a node, I'll get my MV's.

Some shooters use chrono SD's to tell them where their accuracy nodes are by the looking for a group of SD's that are low. In your case, that would be like from 42.9 to 43.5. Then do an OCW within that range and testing different seating depths. I've never done that and just stick to the OCW method.

BTW: QuickLoad is not available to download. It only comes by way of a CD that you must purchase. The reason for that is that QL is produced in Germany (CD sold in US and other places) and their laws don't allow this kind of app to be available for outside the country by way of download. But there's one you might look at if you don't want to buy QL and it's called Gordons Reloading Tool.

 

[redbullitt]

Good call on the magnetospeed possibly making things iffy on the ocw.

What is distance to target in OP? If 100m, I would shoot a longer distance if possible. The ocw is always easier to read a bit further out imo, say 200 or 250 before wind starts to be noticeable.

If you feel there were no flyers you can claim, I like 42.0 to 43.0, then maybe mess with seating depth a bit and see what happens.

 

[ctcash]

When doing an OCW, it works best if you don't have anything attached to the barrel like a MagnetoSpeed (BTW, I uses one too). Maybe you've used an attachment device where it's not on the barrel??? I do OCW without the MS to be sure I'm getting the best reading on paper as something attached to the barrel can throw groups off. Like on my 24" Krieger barrel, I get groups with the MS comparable to groups without it, though still not quite the same. While group sizes are close to the same for me, my POI is shifted 12 o'clock by ~ 2.5". So, I'll shoot my OCW without my MS, then later, when I've pretty much determined that I've found a node, I'll get my MV's.

Some shooters use chrono SD's to tell them where their accuracy nodes are by the looking for a group of SD's that are low. In your case, that would be like from 42.9 to 43.5. Then do an OCW within that range and testing different seating depths. I've never done that and just stick to the OCW method.

BTW: QuickLoad is not available to download. It only comes by way of a CD that you must purchase. The reason for that is that QL is produced in Germany (CD sold in US and other places) and their laws don't allow this kind of app to be available for outside the country by way of download. But there's one you might look at if you don't want to buy QL and it's called Gordons Reloading Tool.

This is a great app, especially for being free. Thank you for sharing. It shows 4064 at 94.2% of max pressure. Would you say that QL is more reliable?

 

[ctcash]

Good call on the magnetospeed possibly making things iffy on the ocw.

What is distance to target in OP? If 100m, I would shoot a longer distance if possible. The ocw is always easier to read a bit further out imo, say 200 or 250 before wind starts to be noticeable.

If you feel there were no flyers you can claim, I like 42.0 to 43.0, then maybe mess with seating depth a bit and see what happens.

I set it at 100 yds. That would be something to consider for sure. I may set a target at 100yds and 200yds to test the difference.

 

[ShtrRdy]

I ended up using Varget with the 175 gr SMK in my .308 Win.

It's possible that the Mag-speed is influencing the groups. You really should do the OCW test without the Mag-speed hanging on the barrel.

 

[padom]

IMR 4064 / 175SMK is a very well known combo and there are numerous discussions and testing on this. You can even look up Dan Newberry's sleuthing the FGMM 175SMK load. Pretty well known load with this combo in the 41.9 - 42.3 range. I ended up on 42gr personally. Ive reloaded and shot thousands of this combo and I can tell you, those 43+ loads are HOT. No question about it. Federal brass is soft, those primer pockets dont have a chance at those pressures either. Even at 42gr that Federal brass isnt going to last compared to Lapua or LC..

Looking at your target, your results are spot on with everyone elses. I like that 41.7 - 42.3 range which is right in line with everyone elses results with this combo. Id load up a seating depth test with 42gr... Or if you want, load up a smaller OCW in .2gr increments from 41.7 to 42.5 to find the dead center of the node which is probably in that 42.1 - 42.2 range then do a seating depth test.

 

[padom]

Here's a great old SH thread from the man himself, Dan Newberry with all the info, videos, discussions you need regarding the 175SMK and IMR 4064...

Sleuthing the Federal Gold Medal match load... Mk 316 Mod 0?

Okay... the self appointed mall cops of reloading might want to go watch a rerun of Gomer Pyle about now... :) For the rest of us, here's a short video we made today... Sleuthing the Federal Gold Medal Match long range load recipe. - YouTube Dan

www.snipershide.com

 

[straightshooter1]

View attachment 7393108

This is a great app, especially for being free. Thank you for sharing. It shows 4064 at 94.2% of max pressure. Would you say that QL is more reliable?

You're going to have a little learning curve to figure out how to handle the variables as you can't just use all the default setting. This is particularly so when it comes to your powder's burn rate as it will vary from lot to lot of powder. Often, when you use up your powder and buy some new, you'll have to tweak your loads to get back to the accuracy you have developed for the previous lot of powder.

So, in this app . . . take a look at your calculated MV. You see it's a good 100 fps slower than what your chrono got. You'll need to adjust the powder burn rate in this app to make it a more accurate representation of where your charge is for pressure and other results. Make sure you're using the correct case volume of YOUR brass; I used 55.9 gr H2O as that's what my Federal fired brass averages. Note too that your temperature is at 21°C when you say you were at 90°F, so that should be changed to 32°C. That'll all make a significant difference in your pressure.

QuickLoad has been around for a long time and used by many reloaders. I've found it to be quite reliable once I got through the learning curve. I've found this GRT app to be reliable too, to the extent I've used it (which isn't a whole lot). It's a verily new app an it still being improved. The GRT has some features not available in QL, but it's powder database is not as extensive and QL's.

I ran the GRT quickly and here's what I've come up with:

 

[ctcash]

You're going to have a little learning curve to figure out how to handle the variables as you can't just use all the default setting. This is particularly so when it comes to your powder's burn rate as it will vary from lot to lot of powder. Often, when you use up your powder and buy some new, you'll have to tweak your loads to get back to the accuracy you have developed for the previous lot of powder.

So, in this app . . . take a look at your calculated MV. You see it's a good 100 fps slower than what your chrono got. You'll need to adjust the powder burn rate in this app to make it a more accurate representation of where your charge is for pressure and other results. Make sure you're using the correct case volume of YOUR brass; I used 55.9 gr H2O as that's what my Federal fired brass averages. Note too that your temperature is at 21°C when you say you were at 90°F, so that should be changed to 32°C. That'll all make a significant difference in your pressure.

QuickLoad has been around for a long time and used by many reloaders. I've found it to be quite reliable once I got through the learning curve. I've found this GRT app to be reliable too, to the extent I've used it (which isn't a whole lot). It's a verily new app an it still being improved. The GRT has some features not available in QL, but it's powder database is not as extensive and QL's.

I ran the GRT quickly and here's what I've come up with:

View attachment 7393363

Wow, that's a 3.4% difference in pressure. I'm glad I decided to reach out for help. Lot to learn. The "calculate shot groups" option looks handy as well. I may spend some time with that also down the road.

 

[ctcash]

Here's a great old SH thread from the man himself, Dan Newberry with all the info, videos, discussions you need regarding the 175SMK and IMR 4064...

Sleuthing the Federal Gold Medal match load... Mk 316 Mod 0?

Okay... the self appointed mall cops of reloading might want to go watch a rerun of Gomer Pyle about now... :) For the rest of us, here's a short video we made today... Sleuthing the Federal Gold Medal Match long range load recipe. - YouTube Dan

www.snipershide.com

Dan Newberry's site is where I read about the OCW process. Also, where I read the paper from Chris Long, "Critical Shock Wave Theory," about OBT. That rabbit hole started from watching 8541 Tactical on Youtube with John McQuay. Thank you for the video. If Federal is a softer case that allows less reloads, what's the first sign that I need to trash the case?

 

[padom]

Dan Newberry's site is where I read about the OCW process. Also, where I read the paper from Chris Long, "Critical Shock Wave Theory," about OBT. That rabbit hole started from watching 8541 Tactical on Youtube with John McQuay. Thank you for the video. If Federal is a softer case that allows less reloads, what's the first sign that I need to trash the case?

Loose primer pockets....i only got 2-3 reloads out of them

 

[ctcash]

Loose primer pockets....i only got 2-3 reloads out of them

This will be my 2nd reload on those cases. I still have some other once fired Fed's.

 

[padom]

This will be my 2nd reload on those cases. I still have some other once fired Fed's.

I used them because I had a bunch from FGMM factory ammo....once I had to buy brass, its always been Lapua for bolt gun and LC for gasser

 

[ctcash]

I used them because I had a bunch from FGMM factory ammo....once I had to buy brass, its always been Lapua for bolt gun and LC for gasser

I have been looking at Lapua as well for the next purchase for working up a hunting load for Elk. But first things first. I'll use my current setup for perfecting a target load workup and then move to that.

 

[straightshooter1]

This will be my 2nd reload on those cases. I still have some other once fired Fed's.

I use my Federal brass for moderate loads only and I've gotten 12 reloads before I have to trash them. And with the moderate loads, I've had no problems with too loose primer pockets. After 12 reloads I started to get case head separation signs, so I definitely don't want any separation.

For my loads that are up near the max, I use Lapua and Peterson brass. The primer pockets hold up very well in these cases. On all brass that I reload, I use a primer pocket swage gauge (it's like a no - nogo gauge) and check the pockets after depriming and chuck any that don't pass and chuck the whole lot when a lot of them don't pass.

 

[Claluja]

My experience has been same as padom's above. FC brass gets loose fast, especially at 44+ 4064. I switched to Lapua brass for those loads.

 

[ctcash]

I use my Federal brass for moderate loads only and I've gotten 12 reloads before I have to trash them. And with the moderate loads, I've had no problems with too loose primer pockets. After 12 reloads I started to get case head separation signs, so I definitely don't want any separation.

For my loads that are up near the max, I use Lapua and Peterson brass. The primer pockets hold up very well in these cases. On all brass that I reload, I use a primer pocket swage gauge (it's like a no - nogo gauge) and check the pockets after depriming and chuck any that do pass or chuck the whole lot when a lot of them don't pass.

Ballistictools.com has a large and small pocket gauge set for $20. I'll invest in those soon.

 

[Doom]

Read through this and here’s my $0.02 worth.

41.8 to 42.2 gr is the typical node. Corresponds to FGMM loaded with 4064. As for the FC brass, this node seem to not stress the brass based on my measurements. Next node is in the 43 to 43.4 gr range.

Strange thing about the OP’s target is the scatter at 41.7gr.

I just ran the same test with Federal brass. OCW was 41.9gr.

 

[918v]

Strange thing about the OP’s target is the scatter at 41.7gr.

Could be his coal. At a longer coal the scatter might shift to a lower powder charge.

 

[Doom]

Could be his coal. At a longer coal the scatter might shift to a lower powder charge.

Good point. Fyi, My load was with a block or two of jump. Rem 700 chamber. 2.800 COAL.