Round robin load development

[tbrice23]

I'm going do a seating depth test tomorrow at 225 yards. I'm going into the test with at 15 rounds already shot to foul the barrel (fouled with the same components) and I will let the barrel cool between rounds.

The only downside I can think of is having to re-position the bag from shot to shot, but at 225 yards the bag movement from target to target will be very small.

Anyone use this method or have bad test results using round robin?
I've never attempted this, any info is appreciated.
Thanks.

 

[benchracer]

I always shoot round robin style during load development. It has worked well for me and does a good job of distributing error and/or any shot dispersion caused by fouling or barrel heating. I have also found this method to produce repeatable results.

The only variable I can think of that will not be affected by shooting round robin style is environmental conditions.

 

[tbrice23]

Benchracer, I'm shooting 4 groups, 4 seating depths. Do you cool the barrel between shots?

One problem I thought of, this is a thin magnum contour barrel and I'm thinking that by the time I let the barrel cool between all rounds the come back to the start that conditions will change enough to obscure results,
otherwise where shooting all similar rounds together will be affected by more similar conditions.

 

[benchracer]

I cool the barrel between shot strings, rather than between individual shots. When testing seating depth, that typically means 4 shot strings. Powder charge workups normally involve 5 to 7 shot strings for me, depending on what I am shooting.

I alter that for two of my rifles (my .264 WM and my .375 H&H). Both rifles tend to heat up quickly, so I felt the need to limit them to shorter strings during powder charge workup, though neither rifle has shown a tendency to walk the POI from barrel heat. Conversely, I am not afraid to shoot up to 10 round strings from my .223 in cool weather.

In general, I believe it is wise to keep an eye on how quickly your barrel is heating and adjust accordingly. Also watch out for mirage induced by barrel heat. It can be subtle enough that you don't realize you are experiencing it until your groups suddenly open up or change POI.

 

[Canadian Bushman]

Im the opposite in this regard. I never shoot anything round robin. I dont want to distribute the error. I wanna shoot all 3 or 5 shots in one position, during one condition. If i get a flier or make an error i will re shoot. I dont want a random mirage or shifting wind to mask what my load may actually be doing. This lets me notice a good setting sooner and i can look back at the target later on and have less details to remember about what happened during each group.

 

[tbrice23]

I did the test round robin the other day, but I left the range hating life !
I shot two 5 round groups today shooting like groups together with better results.
Its a 270wsm with a thin barrel , I let the barrel cool between shots and conditions just change too much by the time I get to the next round of the same setting shooting round robin.

 

[benchracer]

IMO, the round robin method works best at 100 yards. If you intend to do your load development at longer ranges, it is probably not the best choice. There are a number of methods out there that work. The key is to find the method that makes sense to you, that you have confidence in, and that best fits your equipment, available places to shoot, etc.

 

[tbrice23]

Yes, I can see it working better at 100.