Thread: CBTO new projectile

Then with the saum again I choose a length that was shorter than my max and my other is near my max that iv shot before and has produced good 3 and 6 shot groups

I shot the shorter length first these were shot in 3 3 and 4 with a walk to the target between so say again 5mins max?



This is it after 10 looks a lot better than it did with the first 3



Next was my longer length that iv shot before for some reason and im open to suggestions 3 of my 10 were tight to close the bolt on at first i though brass but then projectiles showed marks when i extracted them but not the whole way around like it was jamming in the rifling could they be seated on the piss? I don’t have means to measure runout quality Forster dies 2x fired ADG brass bergers and a Redding press I wouldn’t have thought so I’m yet to clean the rifle after this morning so il be sure to keep an eye on anything foreign. Anyhow I put those three aside and shot them in the last 4

First three


Started finding the right to chamber rounds here





This one clearly looks like rifling but it’s just the 2 marks nothing on the other side



I did measure most of them as I loaded and think it’d be very unlucky if I happened to miss the 3 long ones when I would have measured near all of them at random

Shots 4-6



Shot 7-10



Their was a scope adjustment of 1moa up and 5 clicks right between the 2 saum photos to.


I still favour the longer seating depth for accuracy while not much it has the edge to me 1.310moa and 0.886 I don’t have the means to measure mean radius as ballistic x wants more money out of me for the feature .

Over all I think a 10 shot group can reveal the 3 shot group that looked bad probably isn’t as bad as id thought every time iv shot the 10 which would only be maybe 5 times iv being pleasantly surprised 40 today and did 10 with eldx in my 708 a few weeks ago.



That’s never being a crash hot load even at 3 shots but 10 shots showed me it’s well and truely enough for my hunting needs .

I thought I’d experience more “shooter fatigue” than I did 20 shots from a 3.3kg 708 shooting a stiff 150 load and 20 from a 3.4kg short magnum shooting 180gns with the best of the 4 groups shot last I was surprised. Was a good shooting day for me they all felt good.

Il check sd soon but their was nothing in it maybe 14.1 and 14.2 I’ll also add the other 17 rounds of that load iv shot to todays 10 and see where that leaves me over 27 shots .

That’s enough testing for me with the saum anyway I’m satisfied tell you what bergers and LRAB are not the best pills to conduct higher volume tests with $$$

Based on the group I favour @gimp what if any scope adjustments could you recommend. I’d missed my gong 4 times over the weekend while validating and looking at the dirt behind the target I thought they went high the next day I put a bit of ply behind the target and realised they were 3 inch’s right . So I’d adjusted 1 moa to the left and hit it center center for the last 2 shots . Then the short seating depth this morning was hitting left of POI so I moved it back right thinking maybe there was more wind than I thought when shooting the gong . But then my tried load was connecting right of POI for the first 3 shots then slowly to the left and back right again for the last couple . I thought it was a pretty calm day when I shot the gongs evening then following morning so pretty much rolled out wind distance was 350 and the gongs 6 inch’s so the 1 moa right was just enough to get a miss.

Cheers

And mean radius for dummy’s is that from poa to the outside of the furthest shot from point of aim?

Originally Posted by Kelton

And mean radius for dummy’s is that from poa to the outside of the furthest shot from point of aim?

Scratch that had a quick google and think I understand it, from the center of the group to the center of the furthest shot that’ll I close the group in its radius?


Edit nope still don’t get it I get where to measure from but not understanding where to measure to

Hey thanks for posting, very interesting. Good shooting too.

Cheers at @Tentman it was fun nice being at the range with time up my sleeve for once here is a previous 6 shots that if it wasn’t for my elevation adjustment would have slotted nicely into the rest so I’m certainly satisfied with the rifle set up

It's essentially impractical to manually measure mean radius. You need to work out where the mean point of impact of your shots is, then measure the radial distance of each shot from that point, then calculate the mean of those. It's simple with the Hornady App but you do have to pay 4 bucks or something to get Group Analysis in Hornady.

The variation between the 2x 10rd groups with your SAUM may or may not show a difference in precision from seating depth - really hard to be confident. 10rd groups with any load should be expected to vary in size by up to + or - 40% from the average, so about 0.9 and 1.3 moa is within that expected range.

Precision from any of them looks good for practical purposes as you say.

I reckon come left 1 click?

Might be getting a carbon ring with those marks on the bullet?

Originally Posted by gimp

Might be getting a carbon ring with those marks on the bullet?

Hard to say iv being very strict on cleaning this barrel for carbon because it took me hours to get one out of the last barrel I swore I’d never let it happen again so I hope not . The signs are the same though apart from pressure spikes be 80 odd on this barrel now with strict carbon cleaning will pull it out this morning and give it a good once over and chamber the dummy round and inspect it

So no obvious difference in precision with the 7mm08 & OAL at SAAMI vs max mag length?

The ol' suppressor bush too tight on the barrel is never helpful

Originally Posted by gimp

So no obvious difference in precision with the 7mm08 & OAL at SAAMI vs max mag length?

The ol' suppressor bush too tight on the barrel is never helpful

Their to random new seating depths different from yesterdays and nope nothing to get excited about the shorter of the the 2 printed the bigger of the 2 groups (splitting hairs) but had the better sd (group that’s left of center) both of them are more than good enough for my max range of 400 yards on red deer sized vitals

@Kelton you can drop around and i can borescope it again for you. Also i can machine out that bush for a decent barrel clearance at the same time.

That kimber of mine had a major difference with the suppressor bushing being industry standard clearance vs being well clearance.

Just absolutely punished my 350yard gong 5 from 5 with a left of plate hold very small target at that range with the 10 power and thick vx3 hd reticle using the load with the better sd and ever so slightly bigger group plates 150x150mm happy Chappy being wanting to use this lrab despite the price

Also using my cds for the eldx so gave it an extra couple clicks to account for loss of velocity and bc uneducated guess and ended up bringing it back down to the eldx mark very usable set up