New chamber and crown

[4xforfun]

To you comp guys.

I just had Spencer rechamber and re crown my best tube..about 700 rounds....He took 1.19 inches off....300 wby, was 30 inches plus break, .334 neck, 17 lb hv contour. Was shooting 80 g RL 25/ 210 bergers, .330 bushing.

I have never had a rechamber job. I don't want to do the whole load development thing again....other than re-adjusting the seating depth (I am going to start at the same amount into the lands that it took before). What would you tinker with...if anything?

 

[Keith Glasscock]

Just a physics observattion - your barrel now has a bit more stiffness. The natural frequency is going to be different, so I think you'll have to adjust charges to find a velocity that shoots well.

 

[alf]

I bet your accuracy load doesn't change.

 

[artbosco]

I have never had a rechamber job. I don't want to do the whole load development thing again....other than re-adjusting the seating depth (I am going to start at the same amount into the lands that it took before). What would you tinker with...if anything?

The rechamber and recrown just changed the barrel's harmonics. Start from scratch. There are no short cuts.

 

[4xforfun]

I have never had a rechamber job. I don't want to do the whole load development thing again....other than re-adjusting the seating depth (I am going to start at the same amount into the lands that it took before). What would you tinker with...if anything?

The rechamber and recrown just changed the barrel's harmonics. Start from scratch. There are no short cuts.

Scratch for me was three diff powders and three different bullets...5 different bushings and numerous seating depths. I am not going there...Ill put 400 more down the tube tweakin it. Life (Mine and the bbls) is too short.

I can't imagin that I would need to switch bushing size. I am going to stick with RL 25 / 210 berger/ Norma brass/ 215 Match. Start with the same jam, and work the powder up and down 2grains in 1/2 grain incruments. But I won't have time between now and match time, so I am just going take a wild guess (which means I ain't going to change anything).

Just a guess..but if I lost bbl length I lost velocity....I may need to add a couple of tenths to get the velosity back...that, theoretically , should bring my tune back. But how much did I loose with an inch cut off....I guess the chrono and my records will give me the answer.

On the other hand...my origanl load development with the big cannons is to bump one whole grain at a time....I NEVER messed with 1/10ths of a grain...ever.

 

[expiper]

You found what works with your powder/primer/bullet combo......go bak to that if it is the same reamer/chamber dims./FB/etc. ....if it DONT work ..then do a lil tinkerin......no need for an additional 1600 rds of load development --grin--.....most of the tune that matters is the loose stuff floatin around between our ears...."headspace"/spacehead.....Roger