when chambering just lately in my 22/250 the bolt is tight to close ,could this be the shoulder might need cleaning not suer if that’s the correct wording .when I do clean the the rifle the brushes dypass that part of the barrel .is the a larger brush that would clean this part of the chamber first shoulder any help ? thanks molly
Cleaning the shoulder in the barrel
- Thread starter Molly
- Start date
Do you use factory ammunition, or reload? I ask because if you reload and do not full size your case it will eventually stretch and give you excessive headspace, which in turn will make closing the bolt stiffer. Or, if you've fired a lot of shots through the rifle you could have a carbon donut forming in the freebore?
Ronin
Distinguished Member
This could be the reason for difficulty chambering
Pro shot make a kit for cleaning chambers which is useful
Len the dog
Well-Known Member
A 410 phospor bronzer brush on a cahamber rod followed by a 410 lamb's tail.
Steff
Well-Known Member
It‘s usually the part that’s denominated as the second shoulder, i.e. where the end of the case neck sits, that needs cleaning.
Thanks for the reply’s will look into a chamber cleaning kit p
Steff
Well-Known Member
This very forward part of the chamber does indeed collect carbon. There is a 90 degree step from the chamber into the freebore area which remains untouched by the bore brush.
The brush size required to attend to this part of the chamber can easily be determined by measuring the outside diameter of the neck of a fire case. On a .308 this will be around. .310". So a .32 or .338 cal. bore brush will get the job done.
The brush size required to attend to this part of the chamber can easily be determined by measuring the outside diameter of the neck of a fire case. On a .308 this will be around. .310". So a .32 or .338 cal. bore brush will get the job done.
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One on top of two
Well-Known Member
Sounds like a bit of neck sizing peasantry could be going on 
Len the dog
Well-Known Member
Which are basically just shotgun jags, brushes & mops but with a rifle rod thread. Who hasn't got a tin full of those bits from over the years, I could open a small museum with mine.just go and buy a chamber cleaning kit, ive used one for 30 years, never hah a problem with any of the chambers on my rifles, pro shot, sinclair, brownells, do them, or make your own if your a tight gitbs.
harrygrey382
Well-Known Member
Must be a UK thing?
Steff
Well-Known Member
If you read my replies you will understand that standard chamber cleaning kits will not solve your problem. The chamber as such is hardly ever affected. It‘s all about the wee bit in the very front of the barrel.
Bottleneck cartridges. The chamber becomes grotty, just as the cartridge cases do, in much the same places. Including the shoulder if obturation is poor. Some are OCD about cleaning their brass, but seem to have a blind spot about cleaning the chamber. Which usually requires a brush, or other thing, of cartridge dimension, not the usual bore cleaning brush.
Specialist two-diameter chamber brushes and mops are available in some sizes. Otherwise an ordinary brass or bronze brush of suitable size will do. These sorts of things:
Rifle Chamber Brush & Swabs - .223 / 5.56mm & .308 / 7.62mm Felt Cleaning Mops
I think it is important to use correct terminology. As cases "stretch" and the shoulder moves forward the headspace reduces. Until there in insufficient or even negative headspace. Excessive headspace is a completely different thing, which does not result in stiff bolt closure.
"Donuts" are not anything to do with carbon build-up. They are something that can develop in the brass, at the neck-shoulder junction, over repeated re-sizings.
Generally carbon in the freebore would normally be removed by normal bore cleaning practises. The problematic carbon might be in the area between where the mouth of the cartridge case ends, and the start of the freebore begins.
The major carbon ring problems however are not in the chamber, but a few inches forward of the throate and leade.
This is where peak pressure occurs, the powder is fully "burning", and hard stubborn "carbon" deposits can form, which may even need abrasive cleaning methods to deal with them, not just chemical action from bore solvents. This can also have detrimental effects on pressure, and accuracy.
This term "second shoulder" is a new one for me. It is not (or should not be) any sort of shoulder.
As you say, carbon can build up in the gap between where the case mouth ends (blue line), and the freebore begins. The green highlighted area in this illustration:
If bad enough it can interfere with chambering, particularly if a round is loaded which has a trim length approaching maximum. It can be stubborn to remove, or at least keep under control. This is where a brush of larger than the usual bore size is needed. A normal size bore brush is unlikely to have much effect.
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