Altering seating depth on factory ammo to tighten groups

[nun_hunter]

When I reload I use the OCW method so find a suitable powder charge that gives me the velocity I want and a low ES/SD and isn't overly sensitive to charge weight/temp etc I then adjust seating depth to fine tune the accuracy which has worked very well.

With this in mind has anyone used a kinetic hammer and a seating die to adjust OAL of factory ammo and seen a change in accuracy?

I'm going to be picking up a 308 which isn't screw cut and will have a 1.5-5×20 scope on it for woodland stalking. As this doesn't need to be super accurate I'm just going to use some factory 170 grain Geco ammo as I done want to faff about reloading plus the noise of testing an unmoderated rifle will upset the neighbours. If the groups are not as small as I'd like is it worth tweaking the seating depth on the factory ammo to see if it alters the accuracy?

 

[stubear]

JMHO and you can tell me to jog on, but I wouldnt risk it - I've no idea what powder is being used in the factory ammo, I've not worked up charge weights and I've no idea what the neck tension is like.

As a result I have no idea how the cartridge will respond to altering the seating depth, or how easy or difficult it might be to do so, or what the neck tension might be at the end of it. You could end up with the bullet falling out in the barrel or hugely over pressure etc etc...

Personally I would get the Geco ammo and if your rifle doesnt like it (mine didnt as it happens) then I'd try some other factory ammo in it. Federal 150gn Power Shok is excellent, very effective on deer and a lot of rifles seem to like Federal ammo - Could be worth a try!

You say yourself the rifle doesnt need to be super accurate so if you're around an inch at 100x that should be more than enough? The Power Shoks get me at or just under an inch in my rifle which is pretty good for factory ammo - Hence why I've not been pursuing reloading with any particular urgency!

I'd like to see if I can work out a good load just for the mental exercise of doing it, and a way to pass those long winter evenings when I'm not out stalking haha!

 

[nun_hunter]

Adjusting seating depth by a few thou each way isn't going to make a safe round suddenly dangerous otherwise we who reload wouldn't do it normally. I have a chrono so can keep an eye on velocity and look for any pressure signs. It's not like I'm planning on jamming the bullet back in the case by half an inch then crimping it in place!

 

[JTO]

It would be interesting to know the depth of any crimp in the factory bullets.

 

[Muir]

If I'm going to that much work I'm going to just reload. ~Muir

 

[nun_hunter]

If I'm going to that much work I'm going to just reload. ~Muir

If consumables and range access were as cheap and easy over here as they are for you then I would agree. I'm just thinking of a cheap easy way to tweak factory ammo if possible.

 

[ChesterP]

If consumables and range access were as cheap and easy over here as they are for you then I would agree. I'm just thinking of a cheap easy way to tweak factory ammo if possible.

If one brand of factory ammo doesn't work for you then why not find another brand that does?

By using a kinetic hammer you'll have to change seating to overly-long then seat back to the precise amount (give or take) to get anything like the consistency you'd need on seating depths for low ES/SD. Some bullets using factory crimps may not be that easy to dislodge using a Kinetic hammer and I wouldn't like to try in those cases!

I agree with Muir. If you don't want to play around with trying various factory loads, then reloading from scratch is the most sensible answer and now that you can get all but primers mail order, I can't see the issue with components. You don't need a range if you have land that you have permission to shoot on to develop a load and check zero.

 

[Southern]

The only time I have done it was with some surplus 8x57IS ammo which was very accurate and fast, but corrosive. I pulled all the bullets with a collet die in a C press, and measured the German flake powder from the first ten. They were all exactly the same charge, to 1/10 of a grain. So I put all the powder in a jar, with the recipe on a label. I then loaded the bullets in once-fired Remington brass and primers, to the same length as the military rounds, applied a Lee Factory Crimp, and shot a cloverleaf from my pre-war Sauer, using its Lyman aperture sight. Satisfied with that, I loaded up some 150-gr Sierras to the same die setting ( ogive ), went back out and shot 3 touching. So I have a recipe and powder for light weight bullets.

But, you already received the correct advice: Try the Geco 170 gr. Then try other inexpensive ammunition, like the Federal 150, 165 and 180 gr, and the Sellier & Bellot, Winchester Power Point and Remington green box, or Hornady Whitetail.

 

[Edinburgh Rifles]

by your own method of reloading you are reverse engineering a factory load but with one major oversight.

By far the biggest influence to accuracy in one rifle is charge level.
It is much more likely that the factory round is not performing in your rifle as the charge is not optimal for your rifle

no amount of tweaking OAL will turn a poor charge into an accurate one.

switch ammo until you find a good one

 

[nun_hunter]

by your own method of reloading you are reverse engineering a factory load but with one major oversight.

By far the biggest influence to accuracy in one rifle is charge level.
It is much more likely that the factory round is not performing in your rifle as the charge is not optimal for your rifle

no amount of tweaking OAL will turn a poor charge into an accurate one.

switch ammo until you find a good one

I have not found that with reloading and the OCW method with having numerous charge weights in sequence that all show a similar velocity /pressure and selecting the middle charge weight and tweaking the OAL I have improved the accuracy. Plenty of examples and evidence of this being the most economical and reliable way to develop an accurate load. Think why does GGG target ammo work so well and accurate in so many rifles if charge weight is the number one accuracy cause? No factory ammo has the powder charge weighed its all thrown straight into the case and so a charge that is optimum is whats needed.

Following this method I got a load for my Creedmoor that I can throw charges straight into the case (once the thrower is set up) and have an ES in single figures and a group under 0.4 inch at 122m.

This was my reasoning behind tweaking the OAL, maybe it's not worth trying but I may give it a go and see what results I get just out of interest.

 

[Yorric]

Nun----- Unless you shoot quite a few shots to get anything like usable statistical data, you will have woken the neighbours up & you already said you didn't want to do that. Also your proposed 5 x scope won't help. It seems like a pointless execise to me. Woodland stalking doesn't need 1000 yard match grade ammo. 100 yard 1" groups will more than suffice & IME almost any well made 308 ammo will do that 1 MOA grouping as 308 is a very tolerant chambering.

Either buy your factory favorite or load some rounds to roughly copy factory velocity (start low rules apply) & get on the ground stalking. Both options are as likely to be equally accurate. The advantage of home loads is that you are in control & can slowly build up a usable database to permit improvement if desired.

Fiddling with OAL on factory ammo gives you no reliable base line IMHO.

Ian

 

[Edinburgh Rifles]

I have not found that with reloading and the OCW method with having numerous charge weights in sequence that all show a similar velocity /pressure and selecting the middle charge weight and tweaking the OAL I have improved the accuracy. Plenty of examples and evidence of this being the most economical and reliable way to develop an accurate load. Think why does GGG target ammo work so well and accurate in so many rifles if charge weight is the number one accuracy cause? No factory ammo has the powder charge weighed its all thrown straight into the case and so a charge that is optimum is whats needed.

Following this method I got a load for my Creedmoor that I can throw charges straight into the case (once the thrower is set up) and have an ES in single figures and a group under 0.4 inch at 122m.

This was my reasoning behind tweaking the OAL, maybe it's not worth trying but I may give it a go and see what results I get just out of interest.

I agree.
But factories don't work up loads either!
They produce ammo based on databases of optimum powders and charge levels (by weight or volume is irrelevant)

They may load by volume but they are doing so for speed based on a charge weight that produces the optimal case fill, burn rate, pressure curve and velocity for any given cartridgeBy the same token, why is PPU (or any other factory round) often so crap?
guarantee you they are not loaded with the same optimum powder type and charge

If charge level was not significant you wouldn't be doing an OCW first
If you could turn a poor accuracy load into an accurate one by tweaking OAL we would all just load a slightly above average weight of powder and adjust OAL until it was accurate.

speaking from experience I did exactly what you propose with some RWS 130gr conepoint ammo in 270 about 10 years ago
It displayed poor accuracy compared to 130gr Norma in my rifle

I succeeded in wasting a load of factory ammo and demonstrating that you can't polish a turd.

if its already inaccurate, swap it for any number of options out there that shoot well in factory rifles
if its moderately accurate, just shoot it, fairly confident you won't impact accuracy significantly just by changing OAL

 

[Woodlander]

No,either reload for it(best option)or find a factory ammo that you're happy with.

 

[25 Sharps]

JMHO and you can tell me to jog on, but I wouldnt risk it - I've no idea what powder is being used in the factory ammo, I've not worked up charge weights and I've no idea what the neck tension is like.

As a result I have no idea how the cartridge will respond to altering the seating depth, or how easy or difficult it might be to do so, or what the neck tension might be at the end of it. You could end up with the bullet falling out in the barrel or hugely over pressure etc etc...

Personally I would get the Geco ammo and if your rifle doesnt like it (mine didnt as it happens) then I'd try some other factory ammo in it. Federal 150gn Power Shok is excellent, very effective on deer and a lot of rifles seem to like Federal ammo - Could be worth a try!

You say yourself the rifle doesnt need to be super accurate so if you're around an inch at 100x that should be more than enough? The Power Shoks get me at or just under an inch in my rifle which is pretty good for factory ammo - Hence why I've not been pursuing reloading with any particular urgency!

I'd like to see if I can work out a good load just for the mental exercise of doing it, and a way to pass those long winter evenings when I'm not out stalking haha!

So measure the shortest and adjust all the others to match, same components, charge weight etc. and within factory minimum tolerance just consistent jump which will help accuracy....

Needs to be measured base to base ogive with a decent comparator though or your going to have bullet inconsistency in the mix which could make things worse!!

 

[25 Sharps]

If one brand of factory ammo doesn't work for you then why not find another brand that does?

By using a kinetic hammer you'll have to change seating to overly-long then seat back to the precise amount (give or take) to get anything like the consistency you'd need on seating depths for low ES/SD. Some bullets using factory crimps may not be that easy to dislodge using a Kinetic hammer and I wouldn't like to try in those cases!

I agree with Muir. If you don't want to play around with trying various factory loads, then reloading from scratch is the most sensible answer and now that you can get all but primers mail order, I can't see the issue with components. You don't need a range if you have land that you have permission to shoot on to develop a load and check zero.

Or measure the shortest and seat the others to match, if they're crimped the seating die will be better at breaking the crimp than a hammer.

The OP has stated load testing with an unmoderated rifle is a no go.

 

[nun_hunter]

Or measure the shortest and seat the others to match, I did this with some PPU 308 ammo ages ago but only a couple of rounds so not enough to check if it actually worked if they're crimped the seating die will be better at breaking the crimp than a hammer. I did this with some hand loads in 222. used the seater die to break the crimp before using the hammer.

The OP has stated load testing with an unmoderated rifle is a no go.

Yep this is the case and after spending hours and loads of rounds on my 222 and recently developing a load for my Creedmoor I just can't be arsed to do it again with the 308, mainly the noise, the time and the expense in powder and bullets. It seems the general consensus is not to bother and just shoot it which I am happy with, I just thought others may have tried this as it seemed to me to be an easy/cheap way to possibly improve on adequate factory ammo.

 

[smokey]

what planet have you justed landed from leave factory ammo alone

 

[nun_hunter]

what planet have you justed landed from leave factory ammo alone

Thanks for your constructive comment

 

[ChesterP]

Yep this is the case and after spending hours and loads of rounds on my 222 and recently developing a load for my Creedmoor I just can't be arsed to do it again with the 308, mainly the noise, the time and the expense in powder and bullets. It seems the general consensus is not to bother and just shoot it which I am happy with, I just thought others may have tried this as it seemed to me to be an easy/cheap way to possibly improve on adequate factory ammo.

How so?

It doesn't seem a cheap way if whilst messing about with factory ammo you make it less consistent and no more accurate. Finding a factory load that shoots well to begin with surely is the more sensible way as any loss in £'s to find adequate hunting accuracy by trying different cartridges is likely to be overshadowed by playing with making ammo which performs poorly in your rifle less consistent which might be the likely outcome? Once you find a good cartridge, stick with it and the cost of getting there will be negligible in comparison with the value in meat of the deer taken compared with constantly messing about with kinetic hammers and seaters which is a questionable method to achieve exacting outcomes from poorly performing ammo in the first place. Just altering seating depth may not be enough to alter barrel harmonics to optimise barrel time for your outfit. Altering loads and bullet combinations may be more likely to.

 

[nun_hunter]

I was thinking if it was possible to turn a 1.5moa factory round into a 1moa round not trying to alter a round that shoots 3-4 moa groups. I've improved group size of handloads by more than that just by seating depth.

I shoot a group of 5 get 1.5moa so take 10 rounds and adjust say 5 10thou longer and 5 10thou shorter, shoot those and see if there is any distinguishable difference. If not then just carry on with the standard rounds but if there is an improvement in the groups then try some more. I have a kinetic hammer and a Lee 308 seating die so it's not going to cost me anything other than an hour and 10 rounds.

I was asking others opinions and experiences in case they had tried it and what happened. The replies indicate it's not worth it but I think I'll give it a go just to satisfy my curiosity.

If I buy 3-4 boxes of factory ammo I'm spending £75-100 and end up shooting a fair bit at the range so I may as well buy 100 Sierra bullets and a tub of powder and I'm already making savings (apart from my time developing a load) and will have a decent load.