Precision reloading problem: Accuracy vs. Headspace ?

[brent373]

Some of you may think this thread belongs in the "reloading section" but I thought I may find more valid experience in the precision rifle section.
Im hoping Jerry or someone with similar experience and expectations of accuracy will stumble upon this and shed some light on the problem for me.

I'm finding that when I load my .338LM brass the 3rd time around, I get a number of cases that are sticky on extraction, with the same load that has never been sticky the hundreds of times it was fired before (in the same rifle, in the same conditions). As well as sticky cases, the more important effect is the decrease in accuracy with these "sticky cases". The looney that use to all but cover 5 shots at 400 yards, has now become something more the size of a cd, and this simply wont do.

I will try to answer some questions before they are asked:

Brass is all Lapua brand, purchased new.
Primers are match grade
300gr. Berger OMT bullets (new batches)
H1000 powder, 87.5 grains
All cases were neck turned from new and properly trimmed as needed.
Components are made into assembled in rounds using a forster coax press, with forster match grade dies.
Case necks as well as loaded rounds are all checked and confirmed for concentricity.

The part that confuses me, is that even after this brass is sized again, the empty casings still chamber and let the bolt close with zero extra force.

My first thoughts are that after multiple firings the brass has stretched to the point where the same height setting on the die is now not enough to account for the "springback" effect of the material meaning that I must adjust my die farther down ? Too much headspace can also cause inaccuracies and case separations at the extreme end, but how much is too much ? .004 thou ? .010" ?

My second thoughts are that the necks and shoulders have work hardened and need to be annealed again, but can this be possible being that the bolt will close on a resized case just the way it should ?

I'd love if someone could educate me a little and help me get back on the paper

thanks,
Brent

 

[caustic]

sticky cases are a sign of over pressure are you sure of your scaling practices? perhaps actually adding more powder to some cases . as from what I read it only happened with some of the rounds.

 

[caustic]

an other thought the seating depth of the rounds are they all the same?
is the neck tension enough to hole the bullets in place or are the moving slightly?

 

[ultimate_monkey]

are you neck sizing or FL sizing? if your only neck sizing, it may be that by the 3rd reload that brass has stretched for much and you need to bump the shoulder of the case back

 

[9x19p]

I think u.m. is right, time to push the shoulder back.

"All cases were neck turned from new and properly trimmed as needed."

 

[caustic]

are you neck sizing or FL sizing? if your only neck sizing, it may be that by the 3rd reload that brass has stretched for much and you need to bump the shoulder of the case back

but he says that it is easy to close the bolt on the brass. if the shoulder was too far it wouldn't close easily and not all cases are effected. .

 

[ultimate_monkey]

but he says that it is easy to close the bolt on the brass. if the shoulder was too far it wouldn't close easily and not all cases are effected. .

not all brass stretches the exact same, and it could be that 3rd fireing that stretches the brass to the point of sticking, not the 3rd loading.. as he did say after the 3rd fireing

 

[guntech]

Is it a Remington 700?

I believe the 700 is not as suitable as Remington thought for that big case. It wouldn't be the first 700 338 Lapua with chambering problems with reloads that I am aware of.

 

[brent373]

I apologize I forgot the mention it is a savage110ba. I have heard it having issues with some loads, but this particular handload has shot well for me until now. I always FL size the brass, and have found neck sizing in just about any caliber to generally produce less accurate results, I think because the necks become sized out of concentricity with the rest of the case. The seating depths are all identical ( My shooter friends tease me about my meticulous loading practices). Ive been shooting this load since discovering it early on last year and all has worked well until now. I do not think the issue lies with the load, but something to do with the brass.

Neck tension is .004", so it should be enough to hold the bullets. I typically single feed them while target shooting anyways, but have not noticed any accuracy changes when shooting from the magazine either.

I did also wonder if my scale was varying the charge on me, so started to weigh a bullet (the same bullet) before and after each charge was dumped to ensure the scale was holding a consistent zero.

 

[DG Photography]

First off your accuracy expectations are a little over the top for a factory Savage to shoot 5 shot groups that you can cover with a loonie everyday all day this just is not realistic with a factory gun at 400 yards. If you want this kind of accuracy you need to also consider your wind reading skills and the capability of the gear you are using as well.

There are so many variables that trouble shooting can be difficult! It could be the ammo absolutely but I would not start there if it were me especially after 2-3 reloads. Is your rifle in proper working condition here is a check list of things to check.

-Excessive copper fouling in barrel/throat area as most guys tell me I clean it like mad no way it is fouled! Well lets just say after I clean it they have there eyes opened! Don't get me wrong too much cleaning is not good either and you need some copper fouling in your barrel but there is a limit.

-Chamber clean and free of oil.

-bedding free of debris and oil very important

-Action screws degreased free of oil dry threads on both action threads and fastener threads.

-Action torqued to spec or predetermined torque for best accuracy.

-Scope rail mating surface free of debris and oil that migrates underneath also make sure threads of rail are clean and dry if loctite is used it must be a dry type!! If you put it on wet it will migrate under your scope rail and cause problems.

-check scope for proper torque on ring to rail clamp and scope is pushed forward while tightening.

-good idea to make sure scope is functioning correctly as well you could swap scope over to known load/rifle

-There is a few other things that I would check but only after exhausting other avenues

Now that you have done this go out and shoot and see if things have improved if not it is time to look at your loads. FYI I have 40 reloads on some of my Lapua brass but I anneal every time or second time and only bump when absolutely necessary. The chamber in the Savage does not require neck turning Lapua brass is very good all you need is a neck thickness sorting stand Redding makes one so does Sinclair. If you are not neck turning correctly which is very easy to screw up by the way especially if you are not using a neck thickness mic and sorting stand with dial indicator as well as correct expander mandrels. Neck turning will not help much in a battle/tactical chamber unless you are uniforming/cleaning up necks on crappy brass or you have found a different wall thickness that works better but I doubt it as the clearance in your neck area of your chamber will probably dictate factory wall thickness for sealing purposes so neck turning for a battle/tactical chamber could hinder performance by not allowing a good seal.

If you need any help I am located in Burlington On I have a lab quality scale that reads to .001 of a GR and also have an annealing machine and will have my Sinclair bump gauge/chamber HS back soon. I shoot at Silverdale and EESA
PM me.

 

[DG Photography]

Some of you may think this thread belongs in the "reloading section" but I thought I may find more valid experience in the precision rifle section.
Im hoping Jerry or someone with similar experience and expectations of accuracy will stumble upon this and shed some light on the problem for me.

I'm finding that when I load my .338LM brass the 3rd time around, I get a number of cases that are sticky on extraction, with the same load that has never been sticky the hundreds of times it was fired before (in the same rifle, in the same conditions). As well as sticky cases, the more important effect is the decrease in accuracy with these "sticky cases". The looney that use to all but cover 5 shots at 400 yards, has now become something more the size of a cd, and this simply wont do.

I will try to answer some questions before they are asked:

Brass is all Lapua brand, purchased new.
Primers are match grade
300gr. Berger OMT bullets (new batches)
H1000 powder, 87.5 grains
All cases were neck turned from new and properly trimmed as needed.
Components are made into assembled in rounds using a forster coax press, with forster match grade dies.
Case necks as well as loaded rounds are all checked and confirmed for concentricity.

The part that confuses me, is that even after this brass is sized again, the empty casings still chamber and let the bolt close with zero extra force.

My first thoughts are that after multiple firings the brass has stretched to the point where the same height setting on the die is now not enough to account for the "springback" effect of the material meaning that I must adjust my die farther down ? Too much headspace can also cause inaccuracies and case separations at the extreme end, but how much is too much ? .004 thou ? .010" ?

My second thoughts are that the necks and shoulders have work hardened and need to be annealed again, but can this be possible being that the bolt will close on a resized case just the way it should ?

I'd love if someone could educate me a little and help me get back on the paper

thanks,
Brent

You do not need to FL resize after each firing you can use the brass fire formed just test the empty cases in the chamber once the case has cooled and contracted. I find best accuracy on multiple fire formings when the brass has stretched to the point of making the bolt real sticky to close and needs a tap to open. Once the bolt becomes difficult to close I bump back .002" or until desired feel on the bolt closing. Excessive resizing will wear your brass out real quick leading to head seperation.

Again I call into question your accuracy expectations do you expect sub 1/4 accuracy all the time??

 

[dfrombc]

I was having the same issue with my 338 Lapua. I'm loading 300 gr SMK's in front of one more grain of powder and I'm using a Weatherby action. Same brass but no neck turn. In the end I had to bump the shoulder back. I couldn't tell you how much as I didn't have a bump gauge when I loaded the last batch. I did this once, problem solved. The next loading cycle I neck sized only and the problem returned. Now I just bump the shoulder back to the same spot every time. Can't say if it's the ideal solution but I now have no issues and it still shoot as well as it ever has.

 

[DG Photography]

I was having the same issue with my 338 Lapua. I'm loading 300 gr SMK's in front of one more grain of powder and I'm using a Weatherby action. Same brass but no neck turn. In the end I had to bump the shoulder back. I couldn't tell you how much as I didn't have a bump gauge when I loaded the last batch. I did this once, problem solved. The next loading cycle I neck sized only and the problem returned. Now I just bump the shoulder back to the same spot every time. Can't say if it's the ideal solution but I now have no issues and it still shoot as well as it ever has.

Was your bolt sticky on closing or just opening? Are you saying
A sticky bolt on closing or opening caused accuracy issues??

 

[Mystic Precision]

Reading your first post, I will quickly give some thoughts.

First check to ensure nothing has shaken loosen. Tear it apart and check all bolts. Muzzled braked boomers shake guns and things go loose. Odds are the accuwedge has worn. Bedding may be needed to get things back on track. scope base screws can loosen just a schnick and drive you insane with a wandering zero - I would blue loctite bolts and glue a rail on a high use braked boomer.

Also, consider the scope. Maybe it is getting beat up? Swapping scopes as a last resort is a good thing but test the ammo next.

Every bore wears. as it wears, the friction increases which raises pressures which at the least, makes a load go out of tune. At most, raises pressures high enough to cause extraction problems.

Please read and amend if I misunderstand you. There are a few things we need to clarify.

I understand that when you FL size the cases, they chamber without any apparent resistance. This is the same process you have done since the start.
You seat in the same way with the same bullets. Seating depths have not been changed - make sure the seating stem hasn't moved by comparing to initial dummy rd. You did make one right?
You check your scale and charge weight. This has not varied since the start.

You get poor accuracy with cases that upon firing, are hard to extract BUT cases that are not hard to extract land where you expect. AGAIN, the ammo was not hard to chamber. This is most critical.

Try and drop a bullet into the case neck of all fired cases segrating those that were hard to extract vs those that weren't. Is it easier to drop a bullet into easy extract case but NOT from a hard extract case?

Measure the case neck thickness again. Compare to what you had at the beginning. Has it changed?

My suspicion is that with brass flow, your case necks have thickened again and some are jamming upon firing. this is causing a pressure spike which is jamming your case in the chamber.

Lapua brass necks are too thick. ideally, they should be 12 thou with a max of 14 thou. Neck tension is also very high. ideally, 2 thou is plenty for a single feed. High neck tension will lead to bullet runout and in some cases, bullet damage.

Never assume any chamber dimension. Measure it - they can vary a huge amount. Ensure there is at least 3 thou per side between the chamber and a loaded rd. The lapua puts out alot of gas and fouling. Clearance is a good thing and doesn't hurt accuracy one bit - the bullet has left long before the neck ever hits the chamber.

You may also need to back off on your load to account for bore wear and the new normal. But it sounds like it is case related and a bit of TLC here should take care of the problem.

Jerry

 

[brent373]

First off your accuracy expectations are a little over the top for a factory Savage to shoot 5 shot groups that you can cover with a loonie everyday all day this just is not realistic with a factory gun at 400 yards. If you want this kind of accuracy you need to also consider your wind reading skills and the capability of the gear you are using as well.

There are so many variables that trouble shooting can be difficult! It could be the ammo absolutely but I would not start there if it were me especially after 2-3 reloads. Is your rifle in proper working condition here is a check list of things to check.

-Excessive copper fouling in barrel/throat area as most guys tell me I clean it like mad no way it is fouled! Well lets just say after I clean it they have there eyes opened! Don't get me wrong too much cleaning is not good either and you need some copper fouling in your barrel but there is a limit.

-Chamber clean and free of oil.

-bedding free of debris and oil very important

-Action screws degreased free of oil dry threads on both action threads and fastener threads.

-Action torqued to spec or predetermined torque for best accuracy.

-Scope rail mating surface free of debris and oil that migrates underneath also make sure threads of rail are clean and dry if loctite is used it must be a dry type!! If you put it on wet it will migrate under your scope rail and cause problems.

-check scope for proper torque on ring to rail clamp and scope is pushed forward while tightening.

-good idea to make sure scope is functioning correctly as well you could swap scope over to known load/rifle

-There is a few other things that I would check but only after exhausting other avenues

Now that you have done this go out and shoot and see if things have improved if not it is time to look at your loads. FYI I have 40 reloads on some of my Lapua brass but I anneal every time or second time and only bump when absolutely necessary. The chamber in the Savage does not require neck turning Lapua brass is very good all you need is a neck thickness sorting stand Redding makes one so does Sinclair. If you are not neck turning correctly which is very easy to screw up by the way especially if you are not using a neck thickness mic and sorting stand with dial indicator as well as correct expander mandrels. Neck turning will not help much in a battle/tactical chamber unless you are uniforming/cleaning up necks on crappy brass or you have found a different wall thickness that works better but I doubt it as the clearance in your neck area of your chamber will probably dictate factory wall thickness for sealing purposes so neck turning for a battle/tactical chamber could hinder performance by not allowing a good seal.

If you need any help I am located in Burlington On I have a lab quality scale that reads to .001 of a GR and also have an annealing machine and will have my Sinclair bump gauge/chamber HS back soon. I shoot at Silverdale and EESA
PM me.

Hi DG,

I wouldn't call them my "expectations" of accuracy. In calm conditions from bags, this rifle has shot tight groupings like i mentioned, regularly with this load. When the wind picks up I will get the lateral dispersion, but the vertical is still very tight in windy conditions. Extreme spreads in velocity are typically single digits or low teens.
I have fully bedded the rifle action to the stock ( which was a vast improvement over the accu-stock ) the floating bolt that savage uses, I machined the face to within a tenth or two square to the back faces of the lock up lugs (may not have been completely necessary but I believe did not hurt) and the stock rails have been removed and a 20MOA steel pic rail bedded to the action. Scope rings are beefy leupold Mk 4 steel rings, that I fully lapped before installing the scope. Al screws are still properly torqued, and have not come loose. I am a machinist by trade and although the Lapua cases were very good from new, I am confident that my neck turned cases are more consistent, although you may be right about not making a difference in the looses chamber. I still have a small batch of the last round of reloads that I am using for comparison. They still shoot how they should, but it is this new batch that is giving me trouble. You've obviously been shooting this caliber a while, and have some ample experience. I am interested in your resizing technique to get 40 loads out of your brass. I will PM you about this. Thanks again.

 

[brent373]

Reading your first post, I will quickly give some thoughts.

Please read and amend if I misunderstand you. There are a few things we need to clarify.

I understand that when you FL size the cases, they chamber without any apparent resistance. This is the same process you have done since the start.
You seat in the same way with the same bullets. Seating depths have not been changed - make sure the seating stem hasn't moved by comparing to initial dummy rd. You did make one right?
You check your scale and charge weight. This has not varied since the start.

You get poor accuracy with cases that upon firing, are hard to extract BUT cases that are not hard to extract land where you expect. AGAIN, the ammo was not hard to chamber. This is most critical.

Try and drop a bullet into the case neck of all fired cases segrating those that were hard to extract vs those that weren't. Is it easier to drop a bullet into easy extract case but NOT from a hard extract case?

Measure the case neck thickness again. Compare to what you had at the beginning. Has it changed?

My suspicion is that with brass flow, your case necks have thickened again and some are jamming upon firing. this is causing a pressure spike which is jamming your case in the chamber.

Lapua brass necks are too thick. ideally, they should be 12 thou with a max of 14 thou. Neck tension is also very high. ideally, 2 thou is plenty for a single feed. High neck tension will lead to bullet runout and in some cases, bullet damage.

Never assume any chamber dimension. Measure it - they can vary a huge amount. Ensure there is at least 3 thou per side between the chamber and a loaded rd. The lapua puts out alot of gas and fouling. Clearance is a good thing and doesn't hurt accuracy one bit - the bullet has left long before the neck ever hits the chamber.

You may also need to back off on your load to account for bore wear and the new normal. But it sounds like it is case related and a bit of TLC here should take care of the problem.

Jerry

Hi Jerry,

You have read and understood everything correctly, The rifle has been fully bedded to achieve the results I was getting earlier, and the steel 20MOA rail is glued to the action as you suggest. All things (except headspace? ) being equal to the dummy round, this problem has started. Just to confirm, the bolt DOES close on a loaded round with the same apparent resistance it closes with on an empty chamber. The case neck thicknesses have grown slightly from the start, maybe .0005-.0008", but the fired cases seem to accept a bullet without resistance. Perhaps my necks need to be turned again ? I have not measured the chamber in this rifle yet, what method do you use to measure chamber dimensions accurately ?

 

[brent373]

Just went and fired 2 of the PREVIOUS batch of loads, and measured the necks after firing at .372", the same loaded rounds before firing were .3655", so I have just a hair over 3 thou per side.
On the latest batch of cases, a loaded round measures .3665" on average, giving a little less than .003" per side.. Sounds like brass IS flowing forward ?

 

[dero338]

correct me if I am wrong, but
.004 seems little high for neck tension
every resizing the brass gets harder and neck tension increase the more you resize, the more it gets harder
if anneal your necks and get a bushing little gigger, it should bring the tension constant solve the problem

 

[dfrombc]

Was your bolt sticky on closing or just opening? Are you saying
A sticky bolt on closing or opening caused accuracy issues??

In my situation the bolt seemed to close without problem but the rounds would stick once chambered. Even it they weren't fired they were tough to extract. Accuracy never seemed to suffer but after a broken extractor I decided that neck sizing may not be sufficient. Since I've started bumping the shoulder back each loading I haven't had an issue.

 

[DG Photography]

Reading your first post, I will quickly give some thoughts.

First check to ensure nothing has shaken loosen. Tear it apart and check all bolts. Muzzled braked boomers shake guns and things go loose. Odds are the accuwedge has worn. Bedding may be needed to get things back on track. scope base screws can loosen just a schnick and drive you insane with a wandering zero - I would blue loctite bolts and glue a rail on a high use braked boomer.



In my
Also, consider the scope. Maybe it is getting beat up? Swapping scopes as a last resort is a good thing but test the ammo next.

Every bore wears. as it wears, the friction increases which raises pressures which at the least, makes a load go out of tune. At most, raises pressures high enough to cause extraction problems.

Please read and amend if I misunderstand you. There are a few things we need to clarify.

I understand that when you FL size the cases, they chamber without any apparent resistance. This is the same process you have done since the start.
You seat in the same way with the same bullets. Seating depths have not been changed - make sure the seating stem hasn't moved by comparing to initial dummy rd. You did make one right?
You check your scale and charge weight. This has not varied since the start.

You get poor accuracy with cases that upon firing, are hard to extract BUT cases that are not hard to extract land where you expect. AGAIN, the ammo was not hard to chamber. This is most critical.

Try and drop a bullet into the case neck of all fired cases segrating those that were hard to extract vs those that weren't. Is it easier to drop a bullet into easy extract case but NOT from a hard extract case?

Measure the case neck thickness again. Compare to what you had at the beginning. Has it changed?

My suspicion is that with brass flow, your case necks have thickened again and some are jamming upon firing. this is causing a pressure spike which is jamming your case in the chamber.

Lapua brass necks are too thick. ideally, they should be 12 thou with a max of 14 thou. Neck tension is also very high. ideally, 2 thou is plenty for a single feed. High neck tension will lead to bullet runout and in some cases, bullet damage.

Never assume any chamber dimension. Measure it - they can vary a huge amount. Ensure there is at least 3 thou per side between the chamber and a loaded rd. The lapua puts out alot of gas and fouling. Clearance is a good thing and doesn't hurt accuracy one bit - the bullet has left long before the neck ever hits the chamber.




You may also need to back off on your load to account for bore wear and the new normal. But it sounds like it is case related and a bit of TLC here should take care of the problem.





Jerry

In my T-Wolf the lapua neck thickness of 15 thou works fine
And does not stick. Neck turning has given me a slight benefit in calm
Conditions. I will try again at 12 thou I only tried 14 thou learn something
Everyday. Okay I have some things to try out thanks for the info