I have a browning xbolt in 7mm prc with 24 inch barrel and a 1:8 twist. Originaly I was shooting hornady precision hunter 175gr factory loads. But I just started reloading for it, and I loaded it with 61gr of Hodgdon Retumbo and 175gr eldx bullets. Recently I upgraded scopes to one with uncapped turrets so I can dial. After sighting it in a 100 yards I used the Vortex geoballistics app to do muzzle velocity tuning. At first I just geust what it was going off of the reloading manual. But I was way off, according to Geoballistics my muzzle velocity is 2473 fps. It shoots very accurately, but i am wondering if I should be worried about it if hunting at 500 yds or less and the biggest animal that I would shoot is a bear. Also, how accurate is the MV tuning?
You are running a light load of Retumbo at 61 grains. The range is 59.9gr to 68.2 gr in the manual for the 175 ELDx. Work your way up to the velocity you desire and try to find the node with the best SD & ES. It will probably be in the 65-67gr range, but work up to it. Always check for pressure signs.
okay, that sounds like a good idea. I already loaded 50 rds or so of the this load though. Should I be concerned about the low velocity at ranges under 500 yards?
Go shoot the 50 rounds at the range. Most people should not be hunting at ranges out to 500 yards. At 300 yards and in, your velocity should be fine. Get your load developed and rifle dialed in before you hunt with it. I highly recommend getting a chronograph if you want to be successful in reloading.
Thanks for the suggestions and help. Do you have any budget chono recommendations?
I would consider the Athlon Rangecraft a good budget option compared to the Garmin. You want a stand alone unit, not one that attaches to your barrel.
I’ll look into it, thanks!
Does anyone know how accurate the geoballistics MV tuning is? Basically how close to my actual velocity it really is. Has anyone tried it against a chronograph?
First, I agree with @RCkauai about getting a chronograph. Second, I second the recommendation of the Athlon Rangecraft for a budget alternative to the Garmin. I’ve had mine for about a year and have been very satisfied. Before that I was using a old style Caldwell chronograph. It works and their cheap, but the radar chronograph is way easier to use.
Okay, yeah I probably should get a chronograph. I don’t have the budget for one of those type right now. Are the Caldwell ones accurate at least? I would be using it very occasionally.
Get the Rangecraft, I use mine for every outing involving long gun and accuracy. It just builds more data. Once you get one and realize what it does for you, you will set it up every time while shooting.
I would get a chronograph and pull apart the 50 loaded rounds you have now to save the components, you can save a little money and develop a good load. No need to shoot 50 rounds of something you don’t like.