6.5CM Load Testing. Help with Analysis Please !

[Lateral]

I spent the weekend with a friend, working up a load for my 6.5cm, using the Hornady 147gn ELD-M, Lapua srp cases, CCI 450 magnum primers, and RL26 powder. We did try Remington 7.5’s, but some were cratering quite badly, even on lower charges, and after two blew out, we scrapp

I worked up some base loads, having looked at Quickload, and looking at various manufactures data.

I wanted to start with the OAL that worked well on the 143 ELD-X, even just as start point, and my friend said he’d read that loading 80thou off the lands were having good results, so we loaded up a number of different weights with each OAL, aiming for a barrel time node indicated by QL.

well we found what appeared to be a node at 2740-2765fps, but the predicted loads for 2859fps were falling well short, and we found we’d hit a lower node, with shorter ELD-X OAL, but still seeing sub 1/2” with the longer OAL.

I can’t complain, but wanted to see if the next node was achievable.

Another batch were loaded that evening, for testing on Sunday.

Frustration, with group results I neither understand, or how to resolve.

The following are four shot groups, all loads shot “round robin”, with time spent between each shot, and then longer between each string.
Each has touching, or better, with the last shot in each group being a flier.

These two, had the same powder charge, but different OAL’s. We actually measured to ogive for consistency, loading 2.187”, & 2.253”.

Both are four shots. A group of 3 within the diamond, and the flier outside. They are like twins !



There are three shots into the corner of the diamond.


Another four shot group, three shots into the bottom hole, one above.


Any suggestions what to try ?

 

[Border]

3 shot groups
Sorry mate, couldn't resist it.

 

[User00040]

Shoot more than 3 shots at a time? Are shooting paper or deer?

Honestly would run 10 rounds back to back from cold bore and start from there and repeat again on another day (different weather conditions would be even better!)

With 3 round groups your sample size is too small.

Take the wisdom of @Muir and seat to mag length first and work up to the speed you need. If it is sub MOA then you are fine for deer stalking within 300 meters.

If you read books from the 50's and 60's a 1 MOA sporting rifle (not benchrest) was considered superb. Deer have not changed, so a 2 or even 3 MOA rifle will still work.

 

[paul o']

Nice work ups , i found 2x 5 shot groups work for me one set at 2.825 book then another at 2.870 for both powders so ten for each load had the same with RS62 and 60 i would catch the odd flyer but with 140 eld-m LP starline with 210 fed m . I have not try'd the 143's as yet ! but have try'd the 147's and they just would not settle down in my rife .under the .75 but still giving the odd flyer 3rd or 4th round ? ,two powders very similar results , the low shot R/H/ B on the 1st target was a cold fowling shot as i had just cleaned it .All are 5 round groups .
....
But if this is a stalking set up light barrel i'd be very happy with what you have .

This was the 147eld-m with IMR 4451 with CCI200 primers there not very good to the point they are crap id say , as you can see this 10 round load and was split 2825 col top row , 2800 col in the bottom row as and they are rubbish for long range target but ok for 300 deer .


A very helpful chap has pointed me at N160 for the 140's 143's so that will be my next adventure .
sorry long winded reply but pictures say more lol.

 

[Lateral]

If it were a stalking rifle, I wouldn’t be posting, but it isn’t, so group size is more important, given the last time out, it was shooting out past 850m.

Loading up 10 rounds of each test round, until you have some idea of how it shoots, is time consuming, and you’ll only come home with a whole bunch of ammunition the will need to be pulled, and re-sized.

Four shots will give me a good idea of what has potential, and what‘s unlikely to work.

I’m hoping that someone who has a better understanding, will have some constructive suggestions, so I can understand what appear to be two nigh on identical groups !

 

[Scooby-3]

Try them touching or into the lands, work your load up again though

 

[Lateral]

Try them touching or into the lands, work your load up again though

Thanks, I’ll be trying a couple of suggestions, but groups 4, & 8, are so similar, I wondered if there was a possible explanation.

We did find the higher node, at 2890-2900fps, and that will be the start point.

 

[Scooby-3]

Was it the same number shot of the group that was the ‘ flier ‘ in both groups?

Perhaps try 5 shot groups going forward?

IMO it should all come together when you find the correct node

 

[25 Sharps]

If it were a stalking rifle, I wouldn’t be posting, but it isn’t, so group size is more important, given the last time out, it was shooting out past 850m.

Loading up 10 rounds of each test round, until you have some idea of how it shoots, is time consuming, and you’ll only come home with a whole bunch of ammunition the will need to be pulled, and re-sized.

Four shots will give me a good idea of what has potential, and what‘s unlikely to work.

I’m hoping that someone who has a better understanding, will have some constructive suggestions, so I can understand what appear to be two nigh on identical groups !

Are you shooting competition? If not those groups are fine for 1000 yards.

Usually when testing and I get this I put it down to head position or grip for the last shot being different for the previous 2

 

[25 Sharps]

If it were a stalking rifle, I wouldn’t be posting, but it isn’t, so group size is more important, given the last time out, it was shooting out past 850m.

Loading up 10 rounds of each test round, until you have some idea of how it shoots, is time consuming, and you’ll only come home with a whole bunch of ammunition the will need to be pulled, and re-sized.

Four shots will give me a good idea of what has potential, and what‘s unlikely to work.

I’m hoping that someone who has a better understanding, will have some constructive suggestions, so I can understand what appear to be two nigh on identical groups !

Interesting notes on the primers, I have been getting similar issues with fed small rifle in lap brass, have both CCI BR4 and 450s here to try. Did the primers physically blow out? That suggests high pressure but would have to high in SRP brass so could be poor primer fit I guess, did they seat notably easier than the CCI?

 

[Sonicdmb73]

A mate of mine has a theory about the last round “flier” that many including myself at times get.
One of his best groups was with a 6x scope and fired almost don’t care fashion, the group size a hole of little more than the bullet size.
The theory that I agree has some merit. If you have a group that’s going well you end up trying too hard for a perfect one. The result is pulling a shot, even if it wasn’t a conscious thing.

 

[Lateral]

Interesting notes on the primers, I have been getting similar issues with fed small rifle in lap brass, have both CCI BR4 and 450s here to try. Did the primers physically blow out? That suggests high pressure but would have to high in SRP brass so could be poor primer fit I guess, did they seat notably easier than the CCI?

The Rem 7.5's were dreadful, which is strange, because it's the exact opposite of what we found in the 20ppc !

I had a quick Google when I got back, and found a post (somewhere) by Lauri, stating that both the Rem 7.5, and Fed 205 had thin cups, so it explains both our findings. There was no flattening of the primers, on any load, and the 450/Rem loads were identical.

I may load a few BR4's, just to compare velocity against the 450's.

With regard to groups 4, & 8, I made an error , one flyer was the 3rd, and the other the 4th shot.


Prepped 100 cases, ready for the next round. All of the loads I posted have been eliminated, and I'll be concentrating on one that appears to have hit the node. I'll find out.

 

[25 Sharps]

The Rem 7.5's were dreadful, which is strange, because it's the exact opposite of what we found in the 20ppc !

I had a quick Google when I got back, and found a post (somewhere) by Lauri, stating that both the Rem 7.5, and Fed 205 had thin cups, so it explains both our findings. There was no flattening of the primers, on any load, and the 450/Rem loads were identical.

I may load a few BR4's, just to compare velocity against the 450's.

With regard to groups 4, & 8, I made an error , one flyer was the 3rd, and the other the 4th shot.


Prepped 100 cases, ready for the next round. All of the loads I posted have been eliminated, and I'll be concentrating on one that appears to have hit the node. I'll find out.

Thin cups doesn’t explain the blown primers though (I’m assuming you mean blown from the back of the case, rather than pierced by the firing pin)

 

[Lateral]

Thin cups doesn’t explain the blown primers though (I’m assuming you mean blown from the back of the case, rather than pierced by the firing pin)

Pierced primers, and others badly cratered. No flattening, still have rounded corners.

 

[Doric]

Interesting notes on the primers, I have been getting similar issues with fed small rifle in lap brass, have both CCI BR4 and 450s here to try. Did the primers physically blow out? That suggests high pressure but would have to high in SRP brass so could be poor primer fit I guess, did they seat notably easier than the CCI?

I found the same with my 6.5 Creedmoor Bergara BMP, CCI 400 primers ruptured on fireing. Changed over to 450s and all is well.

 

[jb1]

I always start off with 3 shot groups and wont change, if 3 shots wont group why bother with 5 ??? If 3 shots do group then work on that load, why chuck another 2 ???

Once you have narrowed down the decent 3 shot load data tweak that and then go on to 5 shot groups 10 if you feel you need reassurance, and why not go with the whole box of 100.

If you are getting those decent groups away from the lands is it really worth going closer and increase pressure when it seems your getting pretty close already to max.

Should have got a 260

 

[Sonicdmb73]

Pierced primers, and others badly cratered. No flattening, still have rounded corners.

I bought a 20 Tac with it was some loaded ammunition which I tested for accuracy and dismantled some to weigh the powder so I could duplicate the load. So I had speed over my chronograph, powder type and weight. The seating depth along with the dies etc the only thing I didn’t know which primer. Not Remington 7 1/2s as they are a different colour.
Could I find which one? I had trouble with the primer going back into the firing pin hole. I didn’t have a pierced primer but came close (I don’t recall which brand). I changed powder in the end I just couldn’t find the right primer.

 

[Raven]

A mate of mine has a theory about the last round “flier” that many including myself at times get.
One of his best groups was with a 6x scope and fired almost don’t care fashion, the group size a hole of little more than the bullet size.
The theory that I agree has some merit. If you have a group that’s going well you end up trying too hard for a perfect one. The result is pulling a shot, even if it wasn’t a conscious thing.

thats so true and i have done the same thing a few times myself

 

[Lateral]

the only thing I didn’t know which primer. Not Remington 7 1/2s as they are a different colour.
Could I find which one?

Did you compare the colour of the active part of the primer ?

They can be quite distinctive.

 

[Sonicdmb73]

Did you compare the colour of the active part of the primer ?

They can be quite distinctive.

No I didn’t to be honest I wasn’t aware of that. I will bear it in mind in future thanks.
I might have some 32’s left from the original rounds might be worth pulling them for a look.