Home Forums Reloading Big Game Rifles FNG needs help/advice

I'm loading 160 gr sst's in a 7mm rem mag. using federal mag primers, and 65 grains of RL-22, I'm only getting 2900 fps out of a 26" barrel. Any ideas? I am leaning towards a chrono error...... I have to tape the diffusors together ever since my father in law bounced a bullet off of the rod. It shows my 243 55gr loads 400 fps slower than they were the last time I checked em, but it is shooting to the same zero, and same holds out to a little over 600 yards. Hopefully with all the knowledgeable people roaming the forum, somebody can point out something new, or confirm my theory to some extent. New chrono parts should be acquired soon, but I'm eager to learn more about what else could be the issue.

I think that's your answer right there. Your chronograph is hosed.

That's what I'm thinking. Do you think new rods and diffusers will fix it? My theory is that the tape is somehow screwing up the sensor. I'm going to try and borrow another guys chrono and see what it says

No. I chrony all the time without diffusers. The diffuser rod sits right in the skyscreen housing, and I suspect something there's been knocked out of wack just a weee bit.

Ok. So I guess I'll start shopping for another chrono haha that sucks

But WAIT---how far are you setting up your chronograph from the muzzle of your rifle? I've found that mine works best about fifteen feet out in front. I don't recall whether the false readings I have seen were high or low, but that may be all you need to do.

Also, the way your OP is written it might be that you are saying the chorongraph has been screwy since your FiL nicked a rod...not sure just exactly what you're saying there.

The chrono is set up at 10 feet from the muzzle. And this is the first time using the chrono since it took that 40 off the rod haha the intriguing thing is I went from 2885 with 63 grains of powder, to a whopping 2900 with 65..... maybe I should try it without the diffusers? What's dishartening is my mini-14 is reading right where it should.....But my 7mag and .243 are both slow.......

Move the chrono to 15' and try again.

Will do.

Or farther 20' or more to avoid the muzzle blast.

Also make sure your chrony is set up square so you are shooting at a true 90 degrees to the sensors and not at an angle across them however slightly.

Yes. At 10 ft muzzle blast might be an issue with a 7 mag. Also, take along a known performer for comparison. I just start with my 22LR.

That's my plan. I got new rods and diffusers so I will set it at 20' and shoot the mini first . And then try the 7mag and 243. My buddy and fellow forum guy said 66 grains of RL22 and 160 gr pill and I'll have all the speed I need. So maybe I'll try that next haha I have absolutely no pressure signs at 65 so 66 won't be a big deal hopefully. With a 26" tube I should be over 2900 shouldn't I? Assuming everything else is good?