Sako TRG-42 owners, experience sought

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island

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Hi all:

I chrony-ed a new load in my TRG 42 this weekend (338 Lapua Mag), and I get some "odd" results, wondering if anyone else has seen this, or if I've simply screwed up (quite likely) :)

My new light load with no muzzle brake on was 2731fps average, according to the chrony. But when I screwed the brake on (changing nothing else), I only went down my 1fps, average (over 8 rounds, low variation)! Seems like the brake should steal a little more velocity than that.

To confirm: My POI was definitely different with the brake then without - I didn't have enough rounds to confirm to my satisfaction, but it looks like 1MOA lower with the brake at 100yds, which would imply a significant loss of velocity with the brake - so I suspect my chrony-ing was wrong, but wonder if anyone else has a comparison?

Thanks!
 
A brake will not significantly effect velocity or accuracy, assuming it is a decent design and is properly installed.
A POI change always occurs as the turbulence of the bullet exiting the barrel is altered.
I have found that with or without brakes on many of my rifles the velocity change is extremely small, but POI shifts significantly.
KK
 
Adding weight to the end of a barrel changes the harmonics. This changes the POI. Velocity should no change.
 
Ah - thanks guys, that explains a lot. I was thinking if my POI was changing then my velocity had to be doing it, but didn't consider that the end of the barrel is now a different shape - makes sense.

I'll figure out what the difference is then and make up tables for both.

Much appreciated!
 
I had some odd readings with my Chrony a while back and contacted Chrony and they said to move it out a bit further because the muzzel blast will cause the problems i asked about(had used 2 chronys one reading lower than the other) I mention this just because i get 3050 fps with 96 grains of H-1000 and thats a mid load, 100grains being about the maximum and 90 being the minimum, and actual testing at 1000 yards proved the higher velocity against the ballistics software.
thats with 250 grain scenars.
 
I had the same issue - have to move the chrony out about 10 feet, and even then sometimes the diffusers fly off in a spectacular flutter, especially with the brake on.
 
I load my own - never bought a factory round, not sure what they go for. Premium match ammo reloaded costs me around $1/round for components (not including brass, which lasts a long long time)
 
factory match ammo from black hills is around 6$ a shot, 300 win mag is cheaper and puts a similar hole in paper but, 6.5x284 ballistics with a 250 grain bullet thats what I like about the 338lap.. all the components are quite available, just not at your local crappy tire. I would only take the 6.5 AI improved or the 6.5 284 as the only cheaper alternative to the 338lap.
 
I know the reason, could be a blown out support leg on that crony. I've heard ,and seen, that they don't stand up too well to .338 rounds fired at them. HA, Talk to ya soon.;)
 
There is some Hornady 338 lapua at Wholesales&Sport for around $80 box of 20.
by the way RedLeg, are you guy have any TRG42 in 338Lapua if not , when are you expecting some?

Gb
 
Remington Ammunition 338 Lapua Magnum 250 Grain Scenar Match Box of 20 is 72.00$ in USA (i don't know what brass they are using ??) so i expect about 80.00$ in canada ??,

actually, i pay 99.00$ USD for Black Hills but only have 10 boxes comming in... I will be OK to share 2 or 3 boxes, will post here when i get them
i'am sure that with the time, price will go down... this caliber is more and more popular
 
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