Please help me interpret these results

[CamTheBam]

Hi Guys,

What are your thoughts on the attached results?

Ruger: RPR 6.5CM 24" factory barrel
Tikka: T3x Tac A1 24" factory barrel

I loaded two sets of similar ammo, and shot them over a Magnetospeed.

Brass: Lapua SRP
Primer: Federal GM205M
Powder: VV N150 37.2gr – 41.0gr
Bullet: Lapua Scenar-L 136gr

The Ruger showed pressure signs at 39.0gr, whereas the Tikka went all the way to 41.0 without any pressure signs whatsoever.

The Tikka showed a promising plateau at 39.0gr, but the Ruger showed no obvious plateaus.

The Ruger produced significantly higher MVs for each powder charge.

Can you infer anything about the two firearms from these results? Does the Ruger have a tighter bore? Is one barrel more susceptible to harmonics than the other, etc.?

Many thanks,

Cam.

 

[Dusty Stevens]

Hows the target look?

 

[Bc'z]

Yes how's the targets look?
It's the only paper that dosen't lie.
Graphs are nice for comparison, but targets hide no secrets. IMO

 

[robert8904]

The 50-60 fps velocity difference is well within production variables of two rifles of the same model. As for earlier pressure signs, Ruger does advertise minimalized chamber and rifling which would tend to increase pressure vs the same load fired in a rifle with more generous chamber and bore sizing. Also, differences in freebore and leade can make a difference.

 

[boltfluter]

The Tikka is top of the line for a factory rifle. The Ruger is the exact opposite. Really no comparison between the two. Tikka for the win! Just my very biased, personal opinion.

Paul

 

[Evan]

The Tikka is top of the line for a factory rifle. The Ruger is the exact opposite. Really no comparison between the two. Tikka for the win! Just my very biased, personal opinion.

Paul

I think you're just jealous of the cool "zzzziiiiipppp" sound the bolt makes from the machining marks in the receiver!

 

[boltfluter]

Evan, it is a cool sound!! I have fixed quite a few "zippy " bolts after fluting them lately. These rifles generally are ok, just not in the same league as a Tikka .

Paul

 

[Bc'z]

Evan, it is a cool sound!! I have fixed quite a few "zippy " bolts after fluting them lately. These rifles generally are ok, just not in the same league as a Tikka .

Paul

Like warm butter smooth!!

 

[Webster]

Hi Guys,

What are your thoughts on the attached results?

Ruger: RPR 6.5CM 24" factory barrel
Tikka: T3x Tac A1 24" factory barrel

I loaded two sets of similar ammo, and shot them over a Magnetospeed.

Brass: Lapua SRP
Primer: Federal GM205M
Powder: VV N150 37.2gr – 41.0gr
Bullet: Lapua Scenar-L 136gr

The Ruger showed pressure signs at 39.0gr, whereas the Tikka went all the way to 41.0 without any pressure signs whatsoever.

The Tikka showed a promising plateau at 39.0gr, but the Ruger showed no obvious plateaus.

The Ruger produced significantly higher MVs for each powder charge.

Can you infer anything about the two firearms from these results? Does the Ruger have a tighter bore? Is one barrel more susceptible to harmonics than the other, etc.?

Many thanks,

Cam.

View attachment 1112857

Plateau's mean zero. They are one shot and don't consider the ES for each powder charge. Shoot at targets.

 

[mike a]

Evan, it is a cool sound!! I have fixed quite a few "zippy " bolts after fluting them lately. These rifles generally are ok, just not in the same league as a Tikka .

Paul

Mine sounded like Velcro. Isn't Velcro a cool tactical thing.

 

[Bc'z]

Mine sounded like Velcro. Isn't Velcro a cool tactical thing.

Or a fat guy wearing corduroy

 

[CamTheBam]

Plateau's mean zero. They are one shot and don't consider the ES for each powder charge. Shoot at targets.

Single shot plateau analysis alone, identified a candidate load, which then produced this ES over the chrono:


Taking that particular candidate load, and shooting it on paper for the first time got me this:


Granted I lucked-out here. Normally I would have expected to see a slightly slacker group that I would then try to tighten-up via bullet seating depth. On this occasion, I was able to skip that last step.

5/5 hits on a 5" gong at 1,000yds and the job's done.

In my experience, I can't develop loads that shoot that tight over a variety of distances, without nailing my ES first. The majority of the hard work is done before the bullets even touch the paper for the first time.

 

[Texas10]

Well, you can't beat that with a stick! Some very impressive shooting, and some great figures. Is that ES and SD over 49 shots?

I'm a little surprised the 205M did that well with such a large charge. Going to have to give it a try.

 

[Bc'z]

Nice work!
See there Virginia factory rifles do shoot small.

I hate to be the one to say this, but does it repeat?
The magneto speed may also be dampening barrel harmonics like a tuner.