Over the years I have noticed that when doing load development, there seems to come a point when all of a sudden the felt recoil increase noticeably.

Today I was at the range sorting out my 9.3x62mm and the same thing happened.

I had started with some loads at 55.5grns of RL15 and slowly increased them to 57.00grns and every thing progress smoothly. But at 57.5 there was a definate increase in the kick...the recoil felt more "harsh" and I swear I could feel/hear/percieve the cartridge slamming into the bolt so to speak...There was absolutely no signs of pressure on the cartridge and bolt lift was normal and this in fact was the charge that gave the best groups...

I have noticed this step in recoil in other loads and caliber combinations too, even my .223...

Any thoughts or comments of this? Others noticed it or am I imagining things?

regards,

Pete

I found the same when I started getting serious with 286gr partitions and VVN550. I didn't have a chrono but I think I would have been around 2350 or 2400 then and there I decided to try some 232gr normas!

Not found it with other rifles just the 9.3.

I have found this with my 25/06 with loads some where near max, and after checking the brass every thing looked ok but when i started to resize the brass the primers just almost fell out.
They were loaded with aa2700 120gr nosler sp.

hivelosity,

I haven't prep'ed these cases again as yet but I will certainly watch how the primers come out and how the easily the fresh primers go in.

In the past I have been lucky in that the best groups have usually occured just before this "recoil step" happens but in this case the groups went from nearly 2" to 3/4"-7/8" with just a half grain increase..

Regards,

Pete

This is where a chrono comes in handy. Especially w/ heavy bullets, a 100fps increase, which is possable, will give you quite a bit more recoil. Even though you may not be showing pressure signs, you are more than likely getting a vel. spike. Next time you see someone using a chrono @ the range, aske if you can run some loads over it. I get asked & don't mind at all.

fredj338,

I will probably do that, I am even considering investing in something like an F1 myself for these very reasons..My next question is, does a velocity spike also equal a pressure spike? And if so, you have to wonder how much?

I recall somebody in my hunting club saying that they knew a commercial Ammo company which would pressure test reloads on their equipment for about $25...I am beginning to think that might be money well spent...

Regards,

Pete

Ditto on the need for chron post. Primer appearance and case stretching are quite imprecise indications of high pressure. The latter is tedious and done only after several hihg pressure loads have been fired. With chrons running around just $70. there is no excuse for "shooting in the dark."

A velocity spike DOES equate to a pressure spike.There is vertually no increase in speed without an increase in pressure. The problem is that once the the efficiency of a chambering is maxed it takes quite a bit of extra pressure to got a relatively small increase in velocity. The increased pressure may be 10 thousand lbs/sq inch more yet generate just one or two hundred (or less) fps.

Like Cossack said; there is no free lunch. If you are getting a 75fps jump in vel. there is a corresponding jump in pressure. Maybe not high pressure, but w/o the chrono, you have no idea where your "low pressure", modest recoil load is.