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Discussion Starter #1
Hey guys

I've got a Remington 700 BDL in 7mm RM. I'm preparing for an elk hunt and was shooting over a chronograph to get my muzzle velocity. Which are listed below:
1: 1473 fps
2: 1454 fps
3: 1426 fps
4: 1402 fps

I'm shooting Federal 160gr Partitions so I know my velocities should be approx 2900 fps (also shot another 7mag from the same box of ammo and the velocity was where it should be). This is a 70s era BDL hasn't been shot nearly enough to be worn out.

The gun also has a Hart muzzle brake but that shouldn't be causing reduced MV.

Any ideas as to what could be causing this? Thanks
 

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JR, Immediately I was going to say your chronograph batteries need replacement but you tested another load and the readings were normal.

Not the rifle, it is the ammunition. I would pull some bullets and weigh the charges. Heck, but in another rifle ammunition from the same box were normal? I still suspect your chronograph. How were the impact points relative to aim?
 

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You've either got undersized bullets or an over-sized bore. If the muzzle brake had too small a hole in it, it would have self destructed by now.
Shooting a .264 Win in a 7 RM chamber gives very similar results but I've never tried a 7RM in a 300 WM chamber so can't say if the same holds true.
Anytime there's an alteration, like installing a muzzle brake, that's the first area to investigate but it can't be done by long distance.

It must sound pretty strange! If it doesn't sound weird, it means the chronograph is making a mistake. Move it out another ten feet to get away from the brake and try again.
 

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sooo?

Is there a difference in felt recoil? Muzzle blast? I'm feeling something ain't right here. Do the rounds even make it to a target at 100yds?
 

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It is HEARING it!
 
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Set your chronograph farther from the bench. If I get mine too close to the bench, the .257 Roberts reads fine; the .257 Weatherby, 5,000+ fps :eek:
 
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Set your chronograph farther from the bench. If I get mine too close to the bench, the .257 Roberts reads fine; the .257 Weatherby, 5,000+ fps :eek:
NOW I understand some MV figures printed on ammunition boxes.
 

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I made good money with a chronograph in the '80s when hunters sighted in before the season. I'd pay $5 for every foot second above what was listed on a Weatherby ammunition box and get a dollar for every foot second below that figure. Some (usually doctors) would pay me $200 a shot for three shots because they couldn't believe Weatherby would lie THAT bad!
 
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That is a novel idea. May plagiarise that just for giggles. :)
 

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Particularly surgeons

Can not tell them ANYTHING. Know that from doing their pilot licence renewal tests.... I like to call their assertive BS by setting a difficult task.
 

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Now it is me almost blurping my ginger and honey tea onto the keyboard.. :D
 

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Discussion Starter #16
JR, Immediately I was going to say your chronograph batteries need replacement but you tested another load and the readings were normal.

Not the rifle, it is the ammunition. I would pull some bullets and weigh the charges. Heck, but in another rifle ammunition from the same box were normal? I still suspect your chronograph. How were the impact points relative to aim?
i'm shooting factory loads, which i've shot through this gun before and never had an issue. The points of impact were inconsistent a bit high/low couldn't identify a pattern.
 

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Discussion Starter #17
Is there a difference in felt recoil? Muzzle blast? I'm feeling something ain't right here. Do the rounds even make it to a target at 100yds?
the brake has been installed for 20+ years with out an issue, It does cause a reduction in recoil but thats it other than all the sound coming back at you. Its a Hart brake so its good quality.

They are making it to the target lol but they're all over the place with in a 6-8" circle.
 

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i'm shooting factory loads, which i've shot through this gun before and never had an issue. The points of impact were inconsistent a bit high/low couldn't identify a pattern.
If it is Remington I would pull the bullets and weigh the loads, even it only is to remove one variable.
 

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Ammo

Going back and re-reading your dilemma I'm guessing your using Federal premium ammo. Which should be fine. You shot another rifle over it with no issues,(same ammo?)so If the brake is removeable i'd try that. Or as said above move your chronograph further out first.
I know it doesn't explain the erratic groups but gotta start somewhere.
 
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