308 OCW results. your comments please.

[Shakeber]

I performed my first OCW yesterday. I was a great day to shoot. Sunny, little wind, ~65 degs. F. I am shooting a Rem. 700 5r in 308. All loads are 3 each in Hornady Match brass, using RL15 under Sierra gameking 165 gr. bullets and Winchester primers. All seated to a c.o.a.l. of 2.75". The loads were:
#1 = 42.2 gr.
#2 = 42.5 gr.
#3 = 42.8 gr.
#4 = 43.1 gr.
#5 = 43.4 gr.
#6 = 43.7 gr.
#7 = 44.0 gr. (max)
#8 = 44.3 gr. (max plus one graduation) no pressure signs thruout test
To me the #2 loads show promise. your comments are greatly appreciated.

 

[Tripwire]

Re: 308 OCW results. your comments please.

Back up to 200 so you can see it happen a little better.

It's at least three consecutive loads hitting the same POI via the same POA that you are looking for.

Pretty groups don't mean shit at this point.......

 

[Shakeber]

Re: 308 OCW results. your comments please.

A friend that helped me get into reloading supplied me with approx. 300 rounds of 308 ammo loaded in different cases all using 44.0 grs. of Win 748 powder. The groups that I shot during the OCW are not that impressive (best group is ~.5 moa). The foulers that I shot on that day were with his loads. The problem is that it is not much fun to shoot his loads plus they are different cases. To my inexperienced eye it seems that 42.2, 42.5, and 42.8 are similar POI and it also seems evident that the group definitely opens up at 43.1. Tripwire, I can get really great groups using FGMM ammo but again not much fun. I'm not looking for "pretty groups". Part of the enjoyment of the journey is the getting there not necessarily the being there.
What would be the difference at 200 yds? The moa should hold true. It is all external ballistics once the bullet leaves the barrel. .5 moa is .5 moa. Am I wrong in this? thanks.

 

[Seawalker]

Re: 308 OCW results. your comments please.

Where did you get the max of 44g for rl15 with 165's? Seems like you might be underpowered and missing a better node higher.

 

[Shakeber]

Re: 308 OCW results. your comments please.

I consulted 5 different loading manuals. Hornady, Speer, Nosler, Sierra, and Lyman I think and the average max was approx. 44.0. I felt this was a good safe max. I will eventually use a chrono to see if the load that I come up with is OK. I'm looking for at least 2600 fps. Thanks Seawalker!

 

[vman]

Re: 308 OCW results. your comments please.

Call me anal, but I think load development at 100 yards is pretty much useless. Sure you can gain something provided you do your part, but so much more info comes from shooting out further.

 

[Seawalker]

Re: 308 OCW results. your comments please.

Something which helps me is to shoot the exact same target each time. It makes it easier to get the same sight picture and makes it more repeatable I believe. You did really well considering that you were shooting bullseyes with crosshairs and squares all at the same time.

Personally for me at 100 yds with OCW, I like the target pattern that has six diamonds on the paper. I can hold on them much easier than squares, bulleyes, or crosshairs. But thats just me, and it might not work for you.

Yes, I think you need to chrono the load on the lower node around 42.5. It seems to be a pretty wide node, but it may not have what you want when you go long. Keep on it, and you'll get 'er tight at the end of the flight.

 

[Bugholes]

Re: 308 OCW results. your comments please.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Seawalker</div><div class="ubbcode-body">Where did you get the max of 44g for rl15 with 165's? Seems like you might be underpowered and missing a better node higher. </div></div>
I believe this is corerct, there should be a higher node. you should be able to get up around 46. Do another test starting at 44, look for another node probably between 44.5 and 45.5.

 

[Bugholes]

Re: 308 OCW results. your comments please.

Should have added to make sure youre aware of how pressure signs appear before going over published "max"

 

[Shakeber]

Re: 308 OCW results. your comments please.

Thanks vman, Seawalker, and bugholes. I will take your comments into consideration. Here are the published max. loading for RL15 as I found them:
Hornady 44.3 with 2600 fps
Nosler 44.0 with 2820 fps
Sierra 43.1 with 2700 fps
Speer 47.0 with 2812 fps
Barnes 45.0 with 2793 fps
Swift 46.5 with 2817 fps
Alliant 43.5 with 2675 fps
according to one of these the difference between min load of 41 gr. and max load of 45 gr. is only 250 pfs. So my question is; if there is another node above 44.3 gr. and I gain 100 fps, what is there to gain? Is the extra wear and tear on the barrel worth the difference. Keep in mind that I am loading hunting ammo (hence the 165 gr. gameking). I have a hunting scope on my gun (Leu 4.5 X 14 X 40mm LR with Boone and Crockett reticle) is good to 500 yds with that particular reticle. What am I giving up by settling with the 42.5 gr. and begin adjusting the seating depths? Your comments are greatly appreciated.

 

[kyreloader]

Re: 308 OCW results. your comments please.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Seawalker</div><div class="ubbcode-body">Something which helps me is to shoot the exact same target each time. It makes it easier to get the same sight picture and makes it more repeatable I believe. You did really well considering that you were shooting bullseyes with crosshairs and squares all at the same time.

Personally for me at 100 yds with OCW, I like the target pattern that has six diamonds on the paper. I can hold on them much easier than squares, bulleyes, or crosshairs. But thats just me, and it might not work for you.

Yes, I think you need to chrono the load on the lower node around 42.5. It seems to be a pretty wide node, but it may not have what you want when you go long. Keep on it, and you'll get 'er tight at the end of the flight. </div></div>

I would second the need to shoot the same target on all charge loads. It also makes it hard to interpret because you cannot tell the POA/POI similarities.

Good shooting

 

[Seawalker]

Re: 308 OCW results. your comments please.

It really is hard to tell what you're giving up because you don't know what you actually have right now. Published velocities and actual velocities are a different critter.

For me, first I want the bullet to hit as hard as reasonably possible and as accurately as possible. Certainly if I had to give up one, it would be speed, but speed translates into more energy hitting the animal and also makes for a flatter shooting load. Those are two significant factors in a hunting round.

Many calibers seem to come into their best accuracy with the case nearly full of powder. If I can have both accuracy and speed, then I will take the higher node because it is in my opinion more efficient and more humane. Obviously just my opinion and a decision I can't make for anyone else. Depending on what you hunt, you'll probably still have enough kinetic energy to do the job even with the lower node.

It will take a long time for wear and tear on your barrel to take over shooting hunting rounds. Once you get it set how many rounds do you figure to shoot in the course of a hunting season?

 

[XTR]

Re: 308 OCW results. your comments please.

You really need to get a chrony to work up your loads. If you are planning to shoot 1000yds you need to use 175 SMKs and get your MV up to 2650fps. Based on JBM that barely keeps you supersonic to 1000yds.

Again, this is assuming you are loading 175s to get out to 1000. You can load 168 SMKs for shorter ranges. It doesn't do you any good to be in a node that won't get you to the target super sonic. I'm betting you may have to work up over published maximums. If you're doing it for hunting loads that you're not planning to shoot at long range I might not worry so much about the MV and pick the first node I found.

Shooting for OCW you are not looking so much at group size as you are POI based on the POA. You are looking for 3 groups that are close to the same that way minor fluctuation in MV doesn't have major impact on your POI.

And as others have said, it's better to back up to 200 or 300 yds.

 

[XTR]

Re: 308 OCW results. your comments please.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Shakeber</div><div class="ubbcode-body">I performed my first OCW yesterday. I was a great day to shoot. Sunny, little wind, ~65 degs. F. I am shooting a Rem. 700 5r in 308. All loads are 3 each in Hornady Match brass, using RL15 under Sierra gameking 165 gr. bullets and Winchester primers. All seated to a c.o.a.l. of 2.75". The loads were:
#1 = 42.2 gr.
#2 = 42.5 gr.
#3 = 42.8 gr.
#4 = 43.1 gr.
#5 = 43.4 gr.
#6 = 43.7 gr.
#7 = 44.0 gr. (max)
#8 = 44.3 gr. (max plus one graduation) no pressure signs thruout test
To me the #2 loads show promise. your comments are greatly appreciated.
</div></div>

If you look your POI is climbing in 1, 2, 3. In 3, 4, 5 they are pretty stable then moves up again in 6, 7, 8.

I'd pick #4

 

[MALLARD]

Re: 308 OCW results. your comments please.

i wouldnt worry about barrel life , if your accuracy goes it will be because of something other then throat erosion, most likely , only high bullet to powder ratio calibers burn up barrels like 220swift. Have you considered a ladder test? Or hunting with solids ? if your going to do an OCW i would put more rounds into the group. Maybe 5-7 ,if your testing allot of weights accuracy will probably get affected by fouling. Probably go with a ladder until you are able to eliminate some numbers. Looks good though, promising. You should probably increase your charge until you see signs of pressure. I dont like testing at 100y either, but that doesnt mean you shouldnt. Your in the initial stage of load development, once you chosen some weights for your next round of testing i would move back.

 

[Tripwire]

Re: 308 OCW results. your comments please.

Three rounds per "group" is plenty for an OCW test if the shooter/rifle is up to the task....shit, I've done it with ONE.

Start with a clean barrel and shoot a "round robin" to reduce the impact that fouling has on the bore during the test....

Sure wish folks that yak about OCW would freaking understand it before they yak.

Group size doesn't mean dick until AFTER the OCW is found, and THEN it's tightened by seating depth adjustments. If you have the REAL OCW then it all falls into place beautifully.

Per load manuals...not a bad way to keep yourself from blowing the hell up but it's all generic data, best case scenario. It applies ONLY to the rifle tested in the lab, and has nothing relevant per precision to your exact rifle, your exact bullet, your exact case capacity, etc. To play at this level you need a chrono to see what YOUR shit is doing, not theirs. Running a QL on your case capacity to know a stopping point isn't a stupid thing to do, either.

Per OCW...Newberry's explanation is VERY good place to start <span style="font-style: italic">understanding </span>it.

 

[Shakeber]

Re: 308 OCW results. your comments please.

I do have access to a chrono. I am currently triangulating the target now. I will post a pic of the results. I agree with Tripwire that at this point in the testing the group size is of little importance. However, I am trying to identify the POI's that are the most similar. If there is a node above my max ( I have stated how I came up with the max. of 44.0) should I look for it? As I mentioned earlier, I did not see any indication of overpressuring at all. I know that the military shoots M118LR ammo thru their M-24's (which my gun has similar barrel characteristics) and the reason that I selected RL15 is because that is used in the new M118LR (43.1 gr. under 175 gr SMK's). I also understand that they are loaded in LC brass which has a smaller capacity. My point is if the military, who has much more experience and unlimited testing of ammo has decided on this load (it is supersonic past 1000 m) why should I push mine much more?

 

[XTR]

Re: 308 OCW results. your comments please.

JBM Ballistics

I may be misunderstanding what you wrote in the post above, but if you've got chrono data look here. Based on the Litz BC for the 165 SGK you'd have to be pushing close to 2900fps to stay super sonic at 1000yds. I think you'll blow something up before you get to that number in a barrel that isn't as long as a pool cue. If you're planning to get to 1000 yds you need a different bullet.

If you're saying that you don't want to push it hotter then I'd probably agree. Personally for a hunting round I'd be happy in the lower node, lower pressures = longer brass life and longer barrel life and a well placed 165 SGK is going to make a dead deer when it gets there even if it at 1800+fps at 400yds, and really, if you want to shoot deer at 500 yds, at that point a 308 may not be the best choice.

 

[Shakeber]

Re: 308 OCW results. your comments please.

XCR, I was merely pointing out that the military has done extensive research into the ammo for their sniper rifles. I do not wish to push my hunting round out to 1000 yds. I am content with having a very well shooting hunting rifle. One comment concerning your very last statement however, If 308 is good enough to take out a 200 lb. enemy combatant at 1000 m, why is it not good enough to take out a 150 lb. deer at 500 yds.? This is meant purely for discussion.

Here are the results of triangulating my initial OCW test target. I made lt. blue triangles from the center of each shot in the 3 shot groups. I then calculated the mean center of the triangles as represented by the green dots. I also measured the drop from the center of the Point of Aim (poa) to the center of the green dot. Here are the results. Your comments are greatly apppreciated.
#1 = 22/32" below
#2 = 20/32" below
#3 = 13/32" below
#4 = 14/32" below
#5 = 20/32" below
#6 = 6/32" below
#7 = 2/32" above
#8 = 1/32" above
Again, your comments are welcome and appreciated.