270 win velocity question?

[Philward]

Link below to photo of groups, 1/2" squares. Top group was 3150fps bottom group with 7828 powder was 2990fps. Rifle is sighted in for different load. I'll have to shoot on a 45° day to see if velocity changes. My Lyman book says with same bullet RL22 max 58.5 @ 2980 out of a 26" barrel, and 7828 max 59 @ 2958 with same barrel. Maybe I'll borrow my SIL's chrono and see what results I get.

https://photos.app.goo.gl/X83J3tEd7EW9JZxy5

 

[Pa Grizz]

I was reading an article by Jack O'Connor and his pet load for the 270 was 60 gr of H4831 I starting working up to 60 grain in my 700MR..60 GRS is all you can fit in the case.It shoots a jagged holes at 100 yards and clock 3050 FPS all day with 130 grains sierra bt

 

[jjmp]

Jack didn't have the great powders we have now either .today the factory 270"s are down loaded, it made it Reputation with a 130's doing 3140/3160 fps . Philward, nice shooting RL/22 edged out imr 7828 both in speed n accuracy , good on you , your 26 inch bbl will gain 25 fps per inch of bbl over a 22 inch bbl Or a 24 inch bbl , cheers !.

 

[Calvin45]

Yes it is entirely possible. Especially in the summer. I've seen RE22 post some incredible velocities in the summer.

I've also seen it produce incredible velocity in the winter and give an unpleasant surprise in the summer.

 

[jjmp]

Why would you shoot your winter loads in the summer ,you know you loaded them hotter ,that's not the powders fault .

 

[Clem Bronkoski]

You don't load Barnes bullets to the same Max charge as jacketed bullets. Barnes has free load data online. Just go to the site and look for your cartridge.

 

[Philward]

Not using Barnes bullets.

 

[Orange Dust]

I've also seen it produce incredible velocity in the winter and give an unpleasant surprise in the summer.

Exactly. I'm betting they also have heavy extractor marks to go along with it.

 

[Philward]

Mine had no extractor marks, no heavy bolt lift, no excessive flat primers or blowby. I was going to take picture of cases and share.

 

[Orange Dust]

Mine had no extractor marks, no heavy bolt lift, no excessive flat primers or blowby. I was going to take picture of cases and share.

I shoot RE22 in my 7WSM and see similar velocity increases in the summer, but get marks if I shoot it in 100deg weather. I would try the load over a friend's chrono, or just shoot a couple at 500yds and check the drop to see if what you are seeing is real. Bet it will drop 100fps in 40deg weather.

 

[baldhunter]

One thing I learned about chronographs is lighting can really affect your velocity readings.I found this out one morning at the range.The range setup was shooting to the east.When I first started shooting I was getting some really high velocities.Shooting those same loads two hours later,the velocity dropped off around a hundred foot per second.What was happening is,there is two windows and is measures the speed by when the first window sees the bullet until the second window sees it.The chronograph is calibrated by these two windows.Why the difference,as the sun was rising,a shadow was cast across the windows,it was throwing off the calibration by just a fraction.I since have changed to a different range where I was shooting to the north.The eyes in the windows are not affected by the shadow and my velocities are very consistent everytime I shoot.I also compared my ProChrono to my Magnetospeed and I was getting about the same readings.

 

[Mike AVM]

I shoot RE26 with 130 TTSX at about 3200 fps with no pressure issues. I also shoot 3100 fps with RE23 and a 140 TSX. Both 0.5 MOA out of my rifle.

 

[jjmp]

Any powder will give you excess pressure shooting in 100 degrees ,I won't shoot in 85 degrees or higher , why ruin brass . Did it once never again .

 

[BHP9]

IMO they look nothing more than a refined Winchester Silvertip.