Pressure signs with starting loads

[Dirty30]

I'm trying to work up a load in my Winchester M54 30-06. I have used both 4350 and 3031 and gotten the same result. I take the manufacturer's max load and reduce it by 10% and am getting a sticky bolt. I have read that improper head space can cause pressure signs in starting loads. I have sized and trimmed my cases to the recommended length, and seated my bullets to the recommended OAL of 3.300. At that length I could feel the bullet bite the rifling, so I seated it .005" deeper. They chamber better now but I am still getting pressure signs long before I should. What am I missing here that is causing me problems? What don't I understand about head space?

[country gent]

Will a bullet enter the mouth of a case fired in this rifle? A to long case to to thick neck may not release the bullet shoing and causing high pressure. Head space on the 30-06 is from the case head to a datum line mid point on the shoulder. Not sizing a case shoulder back enough makes for tight chambering to much over works the brass. Have you slugged your barrel to see if it could be on the tight side? A tight groove bore can increase pressure. A Chamber cast might show some thing slightly diffrent also.

[Larry Gibson]

Might help if we knew what the specifics of your starting loads?


Larry Gibson

[Dirty30]

55 Grains of 4350 behind 165 gr. Sierra SPBT. 44.3 grains of 3031 behind the same bullet. Remington 9 1/2 Large Rifle primer.

A bullet will slide into a fired case easily. The cases did not stretch at all when fired, and there are no visual indications of pressure on the case or primer.

[Mk42gunner]

Dirty30,

Get a new manual. According to my copy of the Sierra Reloading Manual, 5th edition, dated 2003, you are a whole lot closer to the top end loads than the starting loads.

Incidentally, how does the rifle act with a factory load?

Good Luck and be safe,

Robert

[scb]

What do you mean by sticky? The bolt handle is hard to lift? Usually a pressure problem. Handle lifts OK but bolt is hard to move to the rear. Usually a sign of a chamber problem. Pitted or ringed. Does the bolt close easily on a handloaded round? I never use a book more that 3 years old, unless the powder is as old as the book, powders change.

[Dirty30]

The bolt handle is hard to lift.

[fredj338]

Who's max data are you reducing by 10%. Bullets wedged into the rifling is likely the issue. OAL is ALWAYS BULLET & GUN SPECIFIC, regardless fo what ANY data tells you. The closer the bullet is to the lands the higher the pressures. Are you crimping? This also raises pressures. You could just have a tight chamber, short throat, etc, all can lead to higher pressures.
Typically, if you are getting sticky bolt lift, you are also seeing other pressure signs like flattened primers or breech face/extractor marks on the case head.

[Dirty30]

I am using IMR's max data. I don't crimp and I'm not seeing any indicators on the case head. I compared a factory load to a sized case and the shoulder is set back quite a bit further on my handloads. I've adjusted my die out to get the same shoulder dimensions, and I'll seat the bullet deeper. We'll see if that makes a difference.

[jsizemore]

According to my 5th edition Sierra Rifle & Handgun Reloading Data.
165gr SBT COAL 3.330"
IMR3031 Starting 40.8gr @ 2500fps
Max 45gr @ 2700fps

IMR4350 Starting 47.5gr @ 2400fps
Max 56gr @ 2900fps