Anglo Custom Rifle

[John MH]

Well I finally got a chance to shoot my ACRC Surgeon .260 Remington today. I had been holding off while waiting for some of the new Lapua .260 Remington Brass and that arrived last week.

 

Decided on using N160 as I have several tubs and started at 38.0 grains working up with a CCI BR-2 underneath and a 139 grain Scenar on top set 0.010” off the lands.

 

The Lapua Data sheet download gives a maximum N160 load with the Scenar at 40.6 grains giving 2529 fps out of an 18 3/4” barrel with a 1 in 9” twist. My barrel is finished at 26” so I suspect the velocity to be higher (it was at 40.5 grains I was getting 2623 fps).

 

The plan was to shoot over a chronograph as the charge weigh incremented up, I had started to load batches of ten rounds in each increment but at 39.2 grains started to load just 5 rounds in each step.

 

_Charge____Av fps____ES______SD______Group Size (Centre to Centre)

…38.0……....2441…..…22…......…6……....…..0.466”

…38.4…...….2476……..26…......…7……....…..0.655”

…38.6…...….2494…..…44….....…13……...…..0.945”

…38.8…...….2523…..…30…….....11…....…….0.489”

…39.0…...….2528…..…14….....…4…….......…0.562” (10 shot group)

…39.2…...….2539……..11….....…4……..........0.813”

…39.4…...….2561……..17….....…7……......….0.294”

…39.7…...….2575…..…14….....…6…….......…0.321”

…39.9…...….2581…..…18…….....7……......….0.703”

…40.1……....2603…..…24…….....7……......….0.710”

…40.3…...….2608…..…43…....…17…......……0.698”

…40.5…...….2623…..…18….... …5…….......….0.580”

…40.7…...….2636…..…10….... …4…….......….0.476”

…40.9…...….2654…..…20….... …7…….......….0.778”

…41.1…...….2669…..…18….... …7…….......….0.520”

 

I was a little disappointed with the ES on each charge increment as I had trickled each one up, more care and cross checking with the Mxx123 next time.

 

The groups, all shot at 100 metres were not spectacular (probably my bench technique which I’m sure could be improved upon and there was one hell of a mirage from my barrel today; hot and sunny and no wind in the covered firing point. I also know that I pulled to odd shot but I have given the whole picture below and not edited any shots) the best at 0.294” and next at 0.321 followed each other so there may be a sweet spot at around 2570 fps.

 

What I was impressed with was the 0.562” 10 Shot group at 2528 fps.

 

For what I want to use the rifle for groups around ½ MOA will be more than acceptable.

 

Looking at the cases fired at 41.1 grains there is an ever so slight ejector button mark so I don’t think I can go much higher with the N160 but will chance maybe another 0.2 grains on the now once fired cases.

 

 

[baldie]

Finally got to have a play then John.

 

Fine tuning that wont be easy, as its already doing well.

 

If it was me, i,d try 560. You should get that little bit more velocity without extra pressure. Looking at the way the groups are going, and the gradual reduction in vertical, i,d say it wants more speed, as 2600 is not fast for the weight. Also you are shooting a heavy for twist bullet, it may need that little extra to really stabilise. What made you go with a 1 in 9" ?

 

I,d lay bets it would shoot the 123 into bugholes.

[John MH]

Finally got to have a play then John.

 

Fine tuning that wont be easy, as its already doing well.

 

If it was me, i,d try 560. You should get that little bit more velocity without extra pressure. Looking at the way the groups are going, and the gradual reduction in vertical, i,d say it wants more speed, as 2600 is not fast for the weight. Also you are shooting a heavy for twist bullet, it may need that little extra to really stabilise. What made you go with a 1 in 9" ?

 

I,d lay bets it would shoot the 123 into bugholes.

 

 

Hi Dave

 

Mines a 1 in 8" twist, the Lapua Data Sheet was based on a 1 in 9".

 

Will be doing some more testing and also have some N560 as well as RL17 so will give them both a try next week.

 

John MH

[Snowz]

My fireforming load in my 260ai is 2800+ with reloader 17 and 140 bergers

 

R17 will give more fps lower psi than n160 but hotter temps which could be a downside

[terryh]

John,

 

Nice start but a few more mph with the heavy bullets. R17 in my 6.5x47 with 25" 5C barrle clears 2800 fps with no apparent problems so the 260 should manage this with a little bit to spare.

 

Definitly try the 123's possibly the 107s

 

Enjoy!

 

T

[John MH]

Well today managed to hone into a bug hole shooting load. Tried some RL17 with ok results but then went back to N160 and got what I was after, consistent groups between 0.264" and 0.305" at 100m.

 

Settled on 42.5 grains of N160, BR-2 primers, 139 grain Scenars 0.005" off. New virgin Lapua Brass shoots an average of 0.556", once fired, neck sized only and shrinks down to about half that. Didn't get the chrono out today but will run the load over it next week to see what the velocity is, I expect it to be just over 2700 fps.

[John MH]

Well she did good yesterday in her first really challenging match.