Chronograph Reality Check!!!!!!!!!!!

[bullet]

I dropped my Chronograph the first of Dec. and thought I broke it. So I put it back on the tripod and shot a few rounds and did not pay attention to the exact numbers that came up, but just glad to see numbers. Every since then I have had above average velocity recordings. Well some of you have questioned my velocity numbers and even have me doubting or wondering myself. So I ordered a new Chronograph and I will be able to compare my 257-300Wby and my 350 Rem mag. This ought to be interesting. I decided to do this when I fired my 22-250 last week and with factory loads recorded 175fps above what I use to get and my handload was 207fps above my average.

Well, I went to the range this morning and boy was I ever enlightened by the results. Of course I did as Smokin advised me to and lined them up in a row. Well the old chrono was well above the new chrono in velocity. I stood there looking at them wondering why is this happening???? As I looked at both of them in a row I saw it and it jumped right out at me, why had I not noticed it before. Having them both in a row caused me to notice that the old chrono was not folded out flat like the new one. So I took it off the tripod and where I had dropped it in December it had bent the sheet metal just on the end that you fold down and was not allowing the chrono to completely open up an lay flat. This meant that the rear photo cell was pointing in a slight angle toward the front photo cell and this shortened the distance between the two. That means the old chrono was recording the speed over a shorter distance that it was not calibrated for so the speeds were faster. Here are the real results of my 257-300Wby with 2 grains below max load for my rifle and also my 350 Rem Mag. at 2 grains below max load.

First round of 86grs Retumbo 100gr TSX

Second round of 86grs Retumbo 100gr TSX

Third round of 86grs Retumbo 100gr TSX

Average 86grs Retumbo 100gr TSX

Accuracy of the load which was outstanding

RL-25 average at 2grs below max 84grs RL-25 bad accuracy

Average for 350 Rem Mag 225gr Sierra

Well now we know why I was getting such high velocities and also know what the truth is. I think I will stay with the 3850fps because the accuracy was so good. With the 350 Rem Mag I will try 61.5grs of WW748 and see what happens.

 

[GB300wm]

Quite a load you got there bullet. I just got my chronograph in and can't wait to see what those 110 nab's are coming out of my 257 bee. I'm hoping for around 3450. The groups are great though. That's great shooting and I believe 3850 is going to be very flat for you.

 

[bullet]

Quite a load you got there bullet. I just got my chronograph in and can't wait to see what those 110 nab's are coming out of my 257 bee. I'm hoping for around 3450. The groups are great though. That's great shooting and I believe 3850 is going to be very flat for you.

Yes GB300wm, that is one fine group and 3850fps is not shabby for a 100gr TSX by any stretch of the imagination. Will be mighty flat and hit hard and the TSX will hold up when game is close or open when game is far off with these velocities. A friend of mine named Michael reamed my barrel and did a supper job.

 

[GB300wm]

I have some GS custom bullets on order to try. They claim to give more velocity and hold up on game. Have you ever shot them bullet? They may be the answer to your having more velocity and a bullet that will still hold up. I'm wanting the added velocity, but I'll just have to try them and see.

 

[bullet]

Started to order some but had to wait to long to get them. I might try them one day but not plans right now.

With this 86grs Retumbo load moving a 100gr TSX at 3850fps and with only a sight-in of 2" high at 100yds - gives the following potential for this deer and black bear killing round.

Trajectory
100yds +2"
200yds +2.85"
300yds +0.44"
400yds -5.74
Hold on top shoulders at 425yds and good out to 500yds

Energy
Muzzle 3290.7
100yds 2817.3
200yds 2408.2
300yds 2053.3
400yds 1744.2
500yds 1474
Not bad at all for a 100gr bullet

 

[FOTIS]

Nice! :lol:

 

[GB300wm]

WOW bullet, that's what I call as flat as you can get. I will have to wait on the GS bullets too, but I'm in no hurry. Gerard told me at GS that I should be able to get 3800 or real close to it with my 257 bee(100 gr HV). Looks like these bullets have very little bearing surface and don't build pressure as quick as some others. That's the only answer I can see for the increase in velocity. I worked extensively with the Barnes and the AccuBond and I can't seem to get the Barnes to group as well in my gun. Just under an inch with the Barnes and well under a half inch with the AccuBond. I have a couple of groups under 0.2" with the AccuBond. My gun really likes them and 7828. Rl 22 with the Barnes. Strange isn't it. I'm going to try the GS and let you know how it comes out. I'm an accuracy freak though, so they will have to be good for me to be happy with them. I'll let you know my velocities when I get a chance to go out. I have Barnes and AccuBond pet loads to run across the chronograph.

 

[bullet]

WOW bullet, that's what I call as flat as you can get. I will have to wait on the GS bullets too, but I'm in no hurry. Gerard told me at GS that I should be able to get 3800 or real close to it with my 257 bee(100 gr HV). Looks like these bullets have very little bearing surface and don't build pressure as quick as some others. That's the only answer I can see for the increase in velocity. I worked extensively with the Barnes and the AccuBond and I can't seem to get the Barnes to group as well in my gun. Just under an inch with the Barnes and well under a half inch with the AccuBond. I have a couple of groups under 0.2" with the AccuBond. My gun really likes them and 7828. Rl 22 with the Barnes. Strange isn't it. I'm going to try the GS and let you know how it comes out. I'm an accuracy freak though, so they will have to be good for me to be happy with them. I'll let you know my velocities when I get a chance to go out. I have Barnes and AccuBond pet loads to run across the chronograph.

Try this for the establishing the over all length of the TSX in your 257. Look at his picture and this is what I did giving it a whole lot of jump and you saw how accurate the group was.

 

[GB300wm]

Thanks bullet, I will try that. I'm seating out to the second band on the tsx right now to get my best grouping. I've never tried that deep. This is my first weatherby and this freebore thing takes getting used to. I'm used to seating 10 to 50 thousanths off the rifling. I love the rifle and it is the most accurate rifle that I have right now. Very easy to group under an inch. I'm also loving expereminting with it. Got to love that quarter bore speed.

 

[bullet]

Thanks bullet, I will try that. I'm seating out to the second band on the tsx right now to get my best grouping. I've never tried that deep. This is my first weatherby and this freebore thing takes getting used to. I'm used to seating 10 to 50 thousanths off the rifling. I love the rifle and it is the most accurate rifle that I have right now. Very easy to group under an inch. I'm also loving expereminting with it. Got to love that quarter bore speed.

It is not the free-bore as much as it is the TSX. It needs more jump at high speeds than Barnes says it does. Now other conventional bullets I seat just off the lands.

 

[Black-tailed bandit]

I thought that your velocity was a little high for the 350, that looks a lot more realistic.

 

[bullet]

I thought that your velocity was a little high for the 350, that looks a lot more realistic.

Yea Black-tailed bandit, it sure was a little high, over 100fps higher. But a 225gr bullet traveling 2626fps is not a shabby thing and especially when it shoots 3/4" groups at 100yds. I am very pleased with how my 350 Rem Mag cartridge is preforming in my Mod 7.

 

[FOTIS]

I got 2600 with the 225 too from my 673. Almost 30-06 trajectory. Not too shabby!

 

[bullet]

I got 2600 with the 225 too from my 673. Almost 30-06 trajectory. Not too shabby!

Not at all considering it is a 225gr bullet

 

[GB300wm]

bullet, I tried seating the tsx really deep to see what it will do and it was not bad. I got two consecutive 3/4" groups with a 3.124 oal.The loads averaged 3514 with rem 9 1/2 primers and 3490 with fed 215 primers. That was with 71.2 grs rl22. They did tighten up some. Thanks for the info.

 

[bullet]

bullet, I tried seating the tsx really deep to see what it will do and it was not bad. I got two consecutive 3/4" groups with a 3.124 oal.The loads averaged 3514 with rem 9 1/2 primers and 3490 with fed 215 primers. That was with 71.2 grs rl22. They did tighten up some. Thanks for the info.

No problem, glad I could help and those are very respectable velocities and great grouping at those speeds. That will be a real killer of a round.