"Blind" Load Testing

[brown dog]

Just been out with the T3, thought I'd see how its light mountain barrel would treat 155 scenars -really to see if it'd be up to a comp in May.

 

I hate load development, but chatting to Ewen last night hit upon a similar idea to take the psychological bit out of it: shoot with the scope dialled so that the fall of shot lands where you can't see it. In this case I tried it with 'up 20' and a bin bag taped to the target board.

 

I also tried something I haven't done before -firing a shot into each group in rotation so that no group was first or last -all equal in the heat and mirage:

 

The thing that surprised me was that the 'sacrificial' load -44gr - was way the best I was expecting 46gr to be the trump load.

 

0.3 and 0.5 MOA before I gave up trying to shoot well in the heat.

 

[Finman]

Matt,

 

clearly this rifle is a POS...you should sell it

[terryh]

Matt,

 

That's a bit better!!

 

T

[Scotch_egg]

I have never seen the blind zero before. Interesting way to prevent psycing yourself out of a group.

 

 

I have used the "round robin" group test though.

 

Your second group looks promising. May have been a pulled shot ruining a good group.

[baldie]

3 rounds test the shooter. 5 rounds test the gun.

 

 

Stop being a tart.

[brown dog]

3 rounds test the shooter. 5 rounds test the gun.

 

 

Stop being a tart.

 

Never done 5 round groups in my life - load of b'lx talked about them. They're only 'better' if you only fire one group.

 

Which is statistically better:

 

Five 3 round groups or Three 5 round groups.

 

[Deserttech Europe]

Funny baldie,

 

I use tha same quote but exactly the otherway about.

 

Regards

 

Ewen

[baldie]

5, five round groups.

 

Then you REALLY know whether the gun/load shoots.

 

The simple fact is that only five round groups are given any credence in any serious competition.

 

I,ve spent the morning testing allsorts in the new .260, and came to the conclusion at the end of the session , with heavier bullets, it was shooting better, then i ran out of ammo.

 

How did i come to this conclusion ? By shooting 5 round groups. Most, if not all, had i just fired 3 rounds, would have been sub 1/4", but the other two rounds in each group would open the group up to half inch, to 3/4". That told me they were not satisfactory. Had i gone on 3 shot groups, i could have come on here and bragged about a 1/4" all day shooter.

 

The only person i would be kidding....would be me.

[brown dog]

5, five round groups.

 

That's the only part of that post I agree with

[Ronin]

Well

 

 

it reacted to bedding and load development then

 

 

I'll give you twenty quid for it

[c18rch]

Interesting idea the only down side I can think of is if you pull a shot or the wind blows one off you may not know if it was a flier or a result of the load?

 

 

[Andrew]

5, five round groups.

 

Then you REALLY know whether the gun/load shoots.

 

The simple fact is that only five round groups are given any credence in any serious competition.

 

I,ve spent the morning testing allsorts in the new .260, and came to the conclusion at the end of the session , with heavier bullets, it was shooting better, then i ran out of ammo.

 

How did i come to this conclusion ? By shooting 5 round groups. Most, if not all, had i just fired 3 rounds, would have been sub 1/4", but the other two rounds in each group would open the group up to half inch, to 3/4". That told me they were not satisfactory. Had i gone on 3 shot groups, i could have come on here and bragged about a 1/4" all day shooter.

 

The only person i would be kidding....would be me.

 

Two Thumbs up! I shoot three shot groups in rifles that are expected to deliver three shots only (such as my deer hunting rifles)but comp rifles get shot in strings comparable to what they will see in use. A few/four of three-shot groups doesn't say much generally, so I will shoot twenty, three shot groups from my hunting rifles over the course of load development. This insures that what I have attained is consistent and repeatable over several outings.~Andrew

[brown dog]

Two Thumbs up! I shoot three shot groups in rifles that are expected to deliver three shots only (such as my deer hunting rifles)but comp rifles get shot in strings comparable to what they will see in use. A few/four of three-shot groups doesn't say much generally, so I will shoot twenty, three shot groups from my hunting rifles over the course of load development. This insures that what I have attained is consistent and repeatable over several outings.~Andrew

 

Which rather brings me back to the question: Which is statistically better 3 x 5rd groups or 5 x 3rd groups? Data from 15 shots is data from 15 shots.

 

After the earlier emails I looked up a couple of web 'tech' articles on the matter; both advocated 5rds as being more valid as a random sampling of 200000 simulated shots with a normally distributed dispersion -asserting that repeated random 3 shot sampling of a normal distribution produced a non-standard distribution whereas 5 shot sampling showed the normal distribution. Can't follow that logic at all - repeated 1 shot sampling of the 200000 would show the normal distribution.

Dispersion from a fixed point - whether collected as 15 x single shots, 5 x 3rd strings or 3 x5rd strings; data from 15 shots is data from 15 shots.

 

I agree that longer strings should be fired from rifles that are expected to fire longer strings.

But what's really being tested there?

The load?

or the rifle (and how it reacts to heating and fouling)?