[question]developing 308 load on Remington700 ADL

[nidm]

[was originally posted on "Centerfire Rifles - Manually Operated", move here in hope of some suggestions about reload]

Working with my remington700, scope and 308 reload for a few months. this is the first time to get consistent result and working up with the load. Pretty happy with that.

• Rifle: Remington 700 ADL
• Scope: Primary ARMS 4-14X44 FFP 308/223 HUD ACSS
• Ammo: 308 reload. Lake City brass, CCI200, AMAX 168gr, Varget (42~45gr with 0.5gr incremental)
• Setting: sitting with sandbag front and rear

total 40 rounds, with 8 5rds-groups. The middle one is to set zero, then shot in the order from group 1(42gr) to group 7(45gr)

While I am happy with the result, through it is not exactly sub-moa yet, looks promising. The scope is a good one just it is not for benchrest shooting with the chevron reticle. I do have a few questions:

1. Almost sub-MOA if use the best of 4 rounds(out of 5). what should I improve from there?
2. group1(42gr) and group2(42.5gr) are very close to the center, but group 5(44gr) and group 6(44.5gr) though grouping well are to the upper-right corner. what may be the reason?
3. Group7(45gr) is a bit hard to open the bolt after firing. I attached a picture of primers. Is there a pressure sign?

Thanks

[Bastard]

#2 looks close to where you need to be, my guess would be that is just about where you need to be... Ignore the flyer & spend more time shooting as I would be willing to bet that it was more the shooter than the the ammo. use factory match ammo as a base line on what you & your rifle can do

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[scotty99]

[J-cat]

Take your 44.4gr load and adjust the oal in small increments. The group should tighten down to about half inch.

[NorCalFocus]

Your looking for the vertical spread of the group, not the group size in itself.

#2 may be your tightest group, but it also has a good amount of vertical spread. Then you look at 1 and 3 on each side of 2. (I'd also throw out #3 from your testing. Looks like you may have messed that group up. Since your zero was the same charge and it looks much better)See how the groups are even more vertically spread? That means that isn't a very wide node.

43.0, (your zero point) 43.5, and 44 all have similar spread, very little of it. Thats going to be a much wider node. Wide nodes are going to make it easier to stay in the node when going from batch to batch of reloads.

Do another round of testing 3-5 shots each of 43.0 to 44.0 in .02 grain increments. That should help you find the middle of the node. Once you find that, you could play with seating depth. But honestly with a factory Remington chamber and 168's, your not going to be able to get close to the lands anyways. I'd just load them at magazine depth and go shoot.

[Metal God]

I'd say 44gr as well based on the 43.5gr and 44.5gr it seem pretty clear the 44gr load is right in the pocket of that node . With 43gr and 45gr completely washing out .

I'd also agree with the OP that the chevron is tough at first to shoot with . Until you realize it actually allows for more precise aiming . Aim small , shoot small . Next time use a smaller target or mark the target with a small dot in the center then put the tip right on the dot .

[nidm]

folks,

thank you so much for the inputs. I got a trip to the range again, with almost everything the same. The ammo was from the same batch in the original post(I load 10 rounds for each group, so shot 5 first time, and another 5 today).

The only change is as you can tell from the image, the target is a sharper marked cross(one of the fellow calgunners suggested) instead of the dot. The cross works better with the chevron scope.

The result improved significant from last trip, the good ones are:

• group 2(42.5gr): 0.88 in - 5 RDs
• group 3(43gr): 0.80 in - 5 RDs
• group 5(44gr): 0.75 in - 5 RDs
• group 6(44.5gr): 0.75 in - 5 RDs

(I can only identify 4 rounds with one hole slightly larger, so give myself the benefit of doubt).

[nidm]

42.5gr, 44gr and 44.5gr are winners; 43gr is kind of odd

[Bastard]

I usually have found 2 when working a load - an upper and a lower... I usually go with the lower because I would only be shooting at 100 yards as that is all I have available to me locally. now if I were I pushing any further I would work both of them

[Metal God]

Looks good , you clearly shot more consistent this time with 44gr still being pretty good . If those were my groups I'd load some at 43.7 and 44.3 maybe 43.8 and 44.2 instead and see if you can hold the same size group and POI as the 44gr load . My guess is that will confirm the 44gr load is the node you want . If not my bet is it's the 44.2 or 3gr load you ultimately go with

[waveslayer]

You need to be looking at the nodes. What did your chrono show you? What's your ES and SD for those loads?

If you're not in the single digits we need to adjust some things. Have you read the instructions on the OCW test? Go with the middle node, not the lowest or highest. What was the ambient temperature? You will want to know because of it gets hit, you may be over pressured and get a sticky bolt, etc... that's also why you don't want to stay near max when is cold out.

How far of the lands are your loads? That's a big factor, you should start .003" off and go from there. This way of the loafs shoot well seated deeper then as the throat wears down, you won't have to adjust much to keep good accuracy.

Some of the groups look like shooting error with vertical stringing

My wife thinks I only have 3 guns

[Metal God]

Waveslayer : Although pretty much everything you wrote is true . Please don't take this as an attack but I'm not sure how much is relevant here based on this specific load and rifle .

You need to be looking at the nodes. What did your chrono show you? What's your ES and SD for those loads?

I've personally run test that show how consistently you hold your rifle will effect your ES/SD from an ES 11fps to 30fps which resulted in blowing the SD up .

What was the ambient temperature? You will want to know because of it gets hot, you may be over pressured and get a sticky bolt, etc... that's also why you don't want to stay near max when is cold out.

The OP is using Varget which is one of the most temperature stable powders on the market . The fact the OP is posting on Calguns makes me think they are in CA . That leads me to think it's unlikely he loaded the rounds at 20* then shot them at 100* as well as likely being a full grain under max . So temp should not be an issue here .

How far of the lands are your loads? That's a big factor, you should start .003" off and go from there.

Couple things here , The OP is using a Remington 700 which are notorious for having LOOONG leades . He's also using 168gr A-max . Combine those two thing and I'd bet he is at least .100 off the lands and likely more . With that short a baring surface on the bullet my guess is he'll never be able to get close to the lands with that bullet in that rifle .

[nidm]

@Waveslayer@Metal_Dog,

thanks for your help.

just like to clarify/confirm a couple items, I am in bay area. The weather were pretty good during both trip: little wind and temperature was ~70F.

And also I am still green(proud with one year reload experience under my belt), need a couple pointers to understand the terminologies: ES/SD, lands, etc.

Also, with this manufactory 700, I am pretty happy if I can maintain 1MOA consistently.

One last question, it looks like I got two sweetspots with Varget: 42.5 and 44gr. I thought the development should narrow me into one...

[longrange1]

ES= extreme spread=this would be the highest velocity to the lowest of how ever many rounds you shoot for a group

SD=standard deviation=basically the average from the ES above

so round 1 is 2650fps round 5 is 2675 thats the ES from that 5 shot group...the SD is 12fps from the same group

lands=equal the point where the bullet contacts the rifling

personally id re-shoot the exact same test because it looks like your getting more comfortable with the rifle in just 2 trips...but if i had to choose from the second target id go with 43g because if it is warmer outside it will group similar to 43.5g....if its cooler it will group similar to 42.5g.

that said i dont really care for the 43.5g charge because of the high round outta the group unless its a called flyer so thats another reason i say re-shoot the test....if things look the same id play with seating a little both ways if you can with the 43g charge if it dont tighten up any call it good and get some trigger time.

[Metal God]

My understanding of standard deviation is it's what you should expect from shot to shot . It's not the center of your ES . I've recorded ES of 69.7 with an SD of 20.8 .

Temperature is not effecting this load , Maybe at distance but with the components being used @ 100yds IMHO you'd need one hell of a rifle and a shooter to match to notice a difference if at all .