Headspace

[Dunkield]

One for the reloading guru's please.

 

How important is headspace when reloading rifle cartridges?

 

In other words, do you adjust it until it is just right, or play safe and allow a bit of clearance?

 

These rounds would be primarily for hunting.

[MC]

I would assume that you need to know what the headspace is on your rifle as this will affect the overall length of the bullet, or how far the bullet is pushed into the lands when you close the bolt.

 

I know that headspace is quite critical to accuracy, certainly in smallbore as you don't get the reloading option.

[markbivvy]

mry or graham are the boys for this i think.

[DaveK]

mry or graham are the boys for this i think.

 

 

For hunting I wouldn't worry too much. For tack driving on a range it might be a bit more important.

 

Do a variety of reloads and see which one suits the rifle best with grouping. Use that load and experiment with the seating of the bullet until you're happy with it. We've managed thumbnail groups at 100yards with Lorraines .223 remy 700 and cloverleaf at 100 with my .243 using that method.

 

It's horses for courses. Depends how technical you want to get.

[Dunkield]

I think you are confusing Headspace with C.O.L./Bullet jump to rifling?

 

Which is it?

 

It's headspace

 

I have my COL measured, done all that...

 

My first reloads shot quite well, but a couple of them were very tight when I went to close the bolt, so I didn't risk it and pulled them apart later. So I have now played safe and closed the gap between the shell holder and the die when the press is in it's upppermost position.

 

doing that means they will always chamber - no probs, but will that affect accuracy/consistancy in any way that I would notice?

[Dunkield]

Just remember, closing a bolt on a slightly expanded case that is in need of full length resizing is one thing, closing a bolt on a case that is in need of trimming and is crimping the bullet into the case as it enters the lands is entirely different.

 

Thanks Fister.

 

These are once fired Sako cartridges, and they are still under length, so they don't need trimming.

[Graham M]

I think you are confusing Headspace with C.O.L./Bullet jump to rifling?

 

Which is it?

 

It's headspace

 

I have my COL measured, done all that...

 

My first reloads shot quite well, but a couple of them were very tight when I went to close the bolt, so I didn't risk it and pulled them apart later. So I have now played safe and closed the gap between the shell holder and the die when the press is in it's upppermost position.

 

 

That isn’t headspace.

Headspace is the distance between the bolt face and the base of the case. This is set using “Go†and No Go†gauges when the rifle barrel is fitted and can’t be altered by normal reloading techniques.

OK you could fireform your cases so that the shoulder blows forward a little, so causing the base of the case to set back onto the bolt head more tightly. But this isn’t altering your rifle headspace just taking up the extra slack.

G.M.

[mry716]

Headspace is just as critical as COL or any other aspect of reloading.

 

The secret of good reloading and therefore accurate ammunition is primarily ensuring constant specification round to round.

 

If you use Factory ammo and then reload those cases ensure whatever you do, you do the same - exactly the same - to each case. Be consistent.

 

All my ammo is for field use so when FL resizing cases shot in someone else's rifle I try to set the die so that when the resized case is placed in the chamber there is 3 thou. of headspace. I measure this simply by removing the firing pin and spring from the bolt and adding a single layer of masking tape to the base of the case. (Scrap off the excess with a Stanley blade)

 

The case needs its shoulder pushing back in the die until, with the tape added, the bolt just shuts smoothly with a minimum 'feel' of resistance.

 

For field use I would never load ammo with a bullet that was any closer than 20-25 thou from the rifling and if accuarcy is the prime factor would NEVER measure the OAL of any loaded round base of case to bullet tip with a caliper etc. Always measure from the ogive to the case base. (the 'shoulder' of the bullet)

 

RCBS do a special micrometer for the purpose and Stoney Point do a little thing that clips on to your calipers that is cheap easy and very accurate round to round. (you buy an insert for each calibre for a few pence)

 

Bullets are easily damaged at the tip and can give false OAL readings so if you load close to the rifling (less than 15 thou) you can find noticible inconsistencies simply because of pressure differences and it will only take one 'long' bullet to cause a significant variation to your accuarcy. The best and least damaged bullet headss are therefore those with plastic tips.

 

Cases that are the correct length will 'nearly' fit your chamber and will last longer than those that are having to expand on firing more than they need to then of course you will need to resize them back to undersize again. Fire formed cases (previously fired in your rifle) that are just neck sized will last well and give at least 3-5 reloads without a FL size and more consistent ammo but as has been pointed out above do not forget to ALWAYS check the case length and trim just before they reach max size.

[deadeye ive]

My first reloads shot quite well, but a couple of them were very tight when I went to close the bolt, so I didn't risk it and pulled them apart later.

At a risk of talking ******** because I've misunderstood the question I'll procede

 

Are you thinking that the case length /bullet is too long and entering the rifling lands if so try the following .

All using resized brass with no primor or powder btw

Insert bullet ...........a few thou longer than your worked out case lenght so it'll slightly interact with the lands .

Cover bullet in black marker pen or soot off a candle and insert in to rifling and close bolt

 

Remove and set the die accordingly but to insert the bullet further into the casing .re-introduce marker pen and keep going until no marks are left thereby your overall measurement should be just kissing the lands

 

Another way would be using a junior hacksaw and cutting a slit across the re formed brass case insert the bullet again slightly near you worked out lenght and insert into rifling and close the bolt .The action of this should push the bullet further into the casing therefore giving you an exact measurment of a cartridge lenght .

 

You probably know all this and i'm an old man just waffling on :blink:

[Dunkield]

Thanks for the replies so far gents.

 

Just to clarify this is a headspace query NOT a COL/cartridge length query.

 

My cases are once fired and are still under length.

 

I have measured my COL using a Stony Point gauge so I know what that is.

 

That isn’t headspace.

Headspace is the distance between the bolt face and the base of the case. This is set using “Go” and No Go” gauges when the rifle barrel is fitted and can’t be altered by normal reloading techniques.

OK you could fireform your cases so that the shoulder blows forward a little, so causing the base of the case to set back onto the bolt head more tightly. But this isn’t altering your rifle headspace just taking up the extra slack.

G.M.

 

OK so the distance I am referring to is the measurement from the shoulder of the cartridge back to the head of the cartridge. If it simplifies my description, I had an unloaded cartridge do the same, so it isn't COL as it didn't have a bullet head inserted.

[Dunkield]

Here is the section from the Redding Die user guide, hopefully it will still be legible:

 

 

 

 

When I use this method I can only get the cartridges in my .223 (CZ) to load without resistance when the shell holder touches the die, i.e. there is no gap at the fully up position.

 

I guess that just means this particular rifle just has a tight chamber?