High pressure, low velocity?

I recently purchased a model 99 300 savage. It is in good condition, barrel looks like new. I made my own brass out of some 308 Remington brass I had laying around. After testing a dummy round (five times) for chambering issues and COAL, I loaded up some test rounds using Reloader 17, CCI primers, and Hornady 165 gr. SST's. I used the data provided in the Hornady Tenth Edition reloading manual. It shows 40.3 grains as the starting load and 45.1 grains as the hottest load. I shot the 40.3 grain load and I couldn't extract the case without jamming it with a cleaning rod.

Thinking maybe the Remington brass is thicker than the Hornady brass the Hornady people used to develop load data, I reduced the load range down to 32 grains of Reloader 17 (starting load) to 35 grains. The 32 grain load worked ok, but velocity was only 1900 ft. per second. I went to the next load (.5 grains higher.) pretty much the same as the first one. I stepped up, .5 grains at a time until I reached 34.5 grains, and had excessive pressure again. Velocity was only 2100 ft. per. sec.

I've been reloading for 50 years, and have never seen a load with lots of pressure, but no velocity. The bullet is not touching the lands. It's way back because of magazine requirements.

I can only think of two possible reasons: (1) The brass is thicker and won't let the bullet out easily enough, and (2) the powder is burning too fast, igniting way before the bullet nears the end of the barrel.

I considered the possiblity that the brass neck may be too thick, but I didn't have chambering problems so I figured it was ok.

Any input will be appreciated.

Moved your post to the ammo/reloading board as it will get more visibility here and your question has to do more with the ammo than the gun.

One thing I would recommend doing just to rule it out is do a chamber cast to make sure there's nothing screwy with the barrel itself. Bore scoping the barrel would also be a good idea just to make sure there isn't some flaw in it that's causing the pressure spike.

Beyond that, I would try a more seasoned and proven powder for the .300 Savage like H4895 or RE-15 just to see if the problem persists with a different powder.

Some good load info here:
https://www.24hourcampfire.com/ubbth...0_Savage_Loads

Check the neck thickness near the neck shoulder junction of your reformed .308 cases. The brass might be thicker and you may not have any neck clearance to let the neck expand and release the bullet.

Remington brass can be thicker and you might want to try thinner Winchester brass or turn the necks on the Remington brass.

I had a similar problem forming 7.65 Belgian Mauser cases from Remington 30-06 brass and the bottom 1/3 of the neck was too thick and had no neck clearance.

I thought TAC and 4064 were the powder of choice.

I would recommend that you take J. Baker's recommendation to scope the barrel and chamber to heart.
The only time I ever had a low velocity load stick in the chamber, it was caused by a patch of rust in the chamber in a barrel that someone had probably abused.
The round fed into the chamber without any problem but apparently formed to the rough spot when the round was fired.
I had a devil of a time getting the brass unstuck.
After I got the brass out, I scoped the barrel and found the problem.

You shouldn't be seeing high pressure signs with low velocity loads unless your barrel has a very tight chamber.
You can get them with a tight target chambers that some use to get better accuracy, but I would doubt your old Savage 99 has one of those.
If the barrel was formed by a worn reamer, a tight chamber might also be possible, but I have only had one of those out of about 40 new rifles.
I suspect that there might be a rough spot in the chamber.

I would buy some Winchester .300 Savage brass as a baseline for pressure or just buy some factory .300 Savage ammo.
The OP needs to find out if the .308 cases formed to .300 Savage are the problem before blaming the rifle for anything.

Winchester Brass 300 Savage Unprimed Bag of 50 Price:$28.09
https://www.grafs.com/retail/catalog/product/productId/19589

Winchester Super-X Ammunition 300 Savage 150 Grain Power-Point
https://www.midwayusa.com/product/2900118527

Thanks for the tips! I think I'll take it to my gunsmith to get it bore-scoped, just to make sure, turn the necks, switch to Sierra 150's and H4895, and try again! I read posts on the thread J.Baker suggested. Most of the guys there reported 2600 f.p.s. with 150 grain bullets. The Hornady (and Aliant and Berger and Speer) books all show about that for the 165's. Of course, they used bolt guns for their tests.

Maybe I'm expecting too much.

I am a Savage man. I own five of them (all modern guns except this one), so I'll be around. Read you all on other threads!

If you turn the necks and find them thicker above the neck shoulder junction then donuts will form faster than normal and you will start having pressure spikes again.

So see if you have problems with thinner Winchester .300 Savage cases or ammo. And if you want to form cases then you need a ball micrometer to check neck thickness.

http://accurateshooter.net/Blog/rcbsballmicx340.jpg

Before I look at the rifle for problems I get a box of premium ammo to shoot in it.

Sent from my SM-P580 using Tapatalk

Note maximum neck diameter of a loaded round. Should not be larger then .340" See drawing at https://saami.org/