Hi Guys, Its a 300 PRC built around a trued remmington 700 LA connected to a 26" Bartlein 1:9. During load development shooting Hornady 212 ELDX in front of anything greater than 76.6 grains of H1000, the bolt hangs up slightly near the top of the throw. With a little more effort the bolt clicks then opens all the way and extraction occurs normally. I assume the why part is because this is the beginning of an over pressure condition. No other indicators. Does anyone know what is happening mechanically. The brass (Hornady & ADG) is 2nd fire meticulously sized, bumped, trimmed and annealed. The 76.6g of H1000 and the ELDX only gets me to 2950fps. Was hoping for the next higher node. It just seems like I have reached a max load a lot earlier then most. Sugestions?
Gunsmithing Rem Action Hangs Up At the Top
- Thread starter Mikemo
- Start date
I am not sure I know how to answer that. I adjust the press and the Redding types s full length bushing die to bump the shoulder 0.002 with a slight cam over on the press. How would I determine how far the case goes into the die?
This may not be a handloading/ammunition problem.
It could, however, be related to how the scope base is mounted.
The mounting screws for the base may be too long, intruding into the bolt lug recesses. In many cases, the front base screws are shorter, to prevent them from intruding.
Swapping the front two with the rear two (compare the lengths, short ones go front) usually solves this problem.
To find an intrusion, open the bolt, reach up into the top of the bolt lug recess with your finger tip, and feel for the intruding end of the screw. Confirm this by examining the outer edge of the RH bolt lug for scratching.
If it's there, the wrong screws are in front, and need to be rearranged.
No need to ask me how I know...
Hope this helps.
Greg
It could, however, be related to how the scope base is mounted.
The mounting screws for the base may be too long, intruding into the bolt lug recesses. In many cases, the front base screws are shorter, to prevent them from intruding.
Swapping the front two with the rear two (compare the lengths, short ones go front) usually solves this problem.
To find an intrusion, open the bolt, reach up into the top of the bolt lug recess with your finger tip, and feel for the intruding end of the screw. Confirm this by examining the outer edge of the RH bolt lug for scratching.
If it's there, the wrong screws are in front, and need to be rearranged.
No need to ask me how I know...
Hope this helps.
Greg
Thanks Greg, I'll check this out.
I think you will find you have a die vs chamber size issue. If you search google you will find some discussion about this issue on the 6.5 PRC. It seems the SAAMI specs the chamber reamer and the reloading die makers are using don't meet the needs of reloaders. New brass works fine but reloads start having issues after 2-3 firings. Your easiest fix is probably going to be a custom sizing die.
Using a black marker on the case it looks like the sizing stops about 0.140 short of full length. Can this be correct? I would expect it to go nearly all the way to the end of the case.
Boy, you may be correct. I just marked my case and ran it up the die and I can see 0.140 that is not sized. Great.
No worries. The issue—which may not show up for a number of firings, depending on fit, pressure, and brass—is that that web is BARELY chambering anyway, and firing it effectively sticks it to the walls of the chamber. Your primary extraction cam is then having to physically break that brass loose from the chamber wall, even though all the rest of the front portion if the case has depressurized, come down 0.001” or so, and will easily slide out.
That’s the click. Granted, that IS what that cam is there for, but most of the time, it isn’t really forced into heavy use. Stick a casing too bad, and you get to hammer on it, rip rims off, break extractors, break off bolt handles...
Non-belted bottleneck cartridges ALSO need to be headspacing on, and self-aligning with, the shoulder, not the web. Too tight a fit at the back if the case interferes with that arrangement, and doesn’t allow for any self-seating.
Tubb, and others, is pretty noted for his opinion that the back if the case needs to be about 0.0015” smaller, at least.
Fix this up, and you may just see better accuracy as well.
I would rather not go the custom route if I can avoid it. I sent off a message to Hornady about their match grade die. I had to try the Hornady because The Redding was not available when my rifle was done. It looks to be the same situation 3 months later. I measured the base of new brass and sized brass and find the sized brass to be 0.004 larger. That does not sound like it would be enough to make a difference?
I measured the diameter of the base just above the rim on a new case and a sized case with a micrometer and got 0.004 larger on the sized case.
No, not at all. It chambers and shoots fine until I get up to about 76.5 g of H1000. And now that I think about it, it shot fine with Hornady factory ammo going about 2980. Its just the sizing that buggers it up. I'll check around local and see what if any of the local Smith's have come up with. Thanks for your help and great explanation of how the extraction process works.
Have you checked the primary extraction? Facing the lugs and pockets can throw things out of timing
See if the bolt handle is making contact with the ramp at the rear of the receiver
I just had to have my bolt handle moved forward on a brand new Remington Defense 300win. If the bolt isn’t difficult to raise just hangs up before it moves back to begin the extraction that will be the problem. Plenty of videos on it
See if the bolt handle is making contact with the ramp at the rear of the receiver
I just had to have my bolt handle moved forward on a brand new Remington Defense 300win. If the bolt isn’t difficult to raise just hangs up before it moves back to begin the extraction that will be the problem. Plenty of videos on it
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