Reloading question

[sharkhunter]

I have a friend that is just starting to reload and has been trying to load for his 7mm. The accuracy is horrible and he is getting 100fps variance with all his test loads. All the components are right and I have watched him load and don’t see any issue there. He’s loading 162gr Nosler e tip. any ideas !

[joel45acp]

There’s a slew of things that could be incorrect. Case sizing, case trimming, seating depth, proper neck tension, correct powder charge, proper powder for given bullet weight, proper barrel twist for stabilizing said bullet and the list goes on and on and on........ My advise to your buddy is to get several reloading books and read them before you start loading.

[bustacap]

100 fps is a bunch. Could be a combination of things or one.
How is the powder dispensed and weighed?
What powder and how many grains?
What primer and brass?

[PondPopper]

Yea.. Way to many unknowns to make a guess but something is way different for there to be 100fps differences between rounds.. Are all case head stamps the same(brand)? Case capacity differences can cause some problems due to pressure changes. How many times have they been re-sized and trimmed??

[thor0812]

100 fps is a bunch. Could be a combination of things or one.
How is the powder dispensed and weighed?
What powder and how many grains?
What primer and brass?

Powder weight was my first thought. Is he using a digital scale? Auto dispenser? The guy that taught me how to load only used beam scales exclusively. He got a fancy auto dispenser for Christmas one year and started having issues with a known load in a known rifle. Checked the powder weights by beam scale and found them to be inconsistent. Loaded a batch with the beam scale and issue went away

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[Slick8]

That's a lot variance. I'd start with the following.

I'd verify brass is all the same brand and lot. If not replace with known good brass.
Verify charge weight with know good powder that's suitable for the cartridge bullet combo.
Verify neck tension is correct and consist.

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[Killer]

All of what has been said and try a different combination of powder and or bullet. Seating depth can affect accuracy. I would change one major thing at a time load 4 rounds and change something else. Keep the rounds separate and go to the range and see what shoots good in the gun. Every gun is different. Did the gun shoot a certain factory round good at any time.

[muzzlebrake]

All reloading dies are NOT created equal.
Have him borrow another set of dies and check the loads out with those rounds.

[muzzlebrake]

IF this is 7mm Rem Mag with the belted case we would like to know if he is full length sizing or just neck sizing. With belted cases a full length sized case head spaces off the belt. A neck sized only case head spaces off the shoulder. This is due to case stretch on a once fired round. Depending on chamber tolerances that can make a yuge difference in chamber pressures and accuracy and help explain the big velocity spread. Have him fire some factory ammo and see if the groups tighten up and velocity spread decreases. If they do then you would know that the gun likes a full length sized case. It would also tell me the gun might need to find a new home. Belted magnums can be a real finicky PITA to reload for sometimes.

[Hotrodd]

Lots of good info here! As already stated powder weight MUST be consistent, a beam scale is the most accurate. However I really like my RCBS Chargemaster. Always Full length resize and trim. Hope this helps.

[RifleBowPistol]

What powder? I would think that's most likely the biggest problem. That or he has the powder charge backed off too much. That's a big case, trying to find a load that fills the case as much as possible, with the lowest pressure possible, should result in the lowest velocity difference and best accuracy.

Then making sure he has brass that is all from the same lot, it also a good idea, at least of the same brand.

I don't know what would be the best choice for powders for that weight bullet, I used to load 140 gr and 150 gr. Noslers. With those, I found Reloader 19 was best. I also tried Reloader 22, but got too high of pressures, so I went with Reloader 19. Not going to say that would be best for the weight of bullet he is using.

If you have a large variation in case capacity, that will cause quite a bit of pressure difference. That's why having brass of the same lot is a good idea. Then if you have quite a bit of empty case, after the powder and bullet have been loaded, then you can get very different burn rates for the powder, depending on how it's laying in the case, when the primer is set off.

Then the next thing I would check for, with that much velocity variation, is to make sure he is accurately weighing the powder charge. What scale is he using and how meticulous is he when weighing each charge and doing things exactly the same for each charged weighed?

[LWD]

Try a different bullet before changing anything. The Nosler etip is an extremely hard bullet and has a reputation for being, er, difficult.

[RifleBowPistol]

Another thing I forgot, more important with larger magnum calibers. When at the range, truly with any caliber, but bigger calibers are worse. Only fire one round off every couple minutes, maybe every five minutes, if you really want to keep it consistent. After every second shot or even after every shot, check the barrel temp, mid way down, then out towards the end of the muzzle. The barrel will be hottest at the muzzle end. You want the barrel temp consistent, and near ambient temp. If you are firing off rounds every 10 to 15 seconds, then firing off five rounds or more, before taking a break. The barrel will definitely heat up, enough to affect accuracy. One because the barrel will bend slightly as it heats up, then two, if the barrel gets hot enough to where the chamber is hot, you can cook rounds, increasing the powder temp. That will cause the pressures to go up.

So when working up loads, don't get in a hurry.

[cva34]

Some barrels just dont like certain Bullets..Get another brand and try...play with seati
ng depth maybe

[muzzlebrake]

One must remember that full length re sizing will change case net volume ever so slightly. The way to tell how much volume change is to fill with water and weigh the amount of H2o from each. A really loose chamber will let the cases swell more so if that is the case you will easily see the difference. As always the devil is in the details