Pressure Problem Ruined Bolt Please help!

[LHSmith]

The bushings cannot correct brass with necks that vary in thickness, as Remington surely does....they will still be have high and low spots, essentially egg-shaped). The bushings will push the excess inside ...only for the bullet to push it back out.

 

[cliffy]

I agree that warm weather and cool weather don't produce the same results velocitywise or pressurewise. I have warm weather,100 degree) and cool weather,60 degree) loads and even some betwixt. Hodgdon EXTREME powders assist in the battle, but HOT weather presents WOW loads! I add .5 grains below 30 degrees. I cut a full grain back over 90 degrees. cliffy

 

[Glocksig]

Alright got the bolt repaired with a sako extractor this time. Everything else is the same. I just got back from starting the ladder again with the 80 g bergers and 4064. Here's a sample of the minimum load with the 4064 at 38 g

Here's a couple at the minimum,45 g of RL-19 and a Nosler 90 g)

Correct me if I'm wrong but this sure looks like cratered primers to me.

 

[rayjay]

You need to get the firing pin hole bushed. There is too much clearance between the hole and the firing pin tip.

The edges of the primer is still nice and round.

 

[Glocksig]

So I need to be looking for a 'sharp' edge for pressure? I hate to send it off to get more work done and I'm afraid if I get it bushed then pressure will be hard to spot. Could this be a function of replacing the factory assembly with a PTG firing pin assembly?

 

[alf]

Bushing the bolt will not mask high pressure. Flat all the way to the edge primers, case head tatoo, and hard bolt lift will still be there.

The firing pin hole is still too large for the clearance of the PTG firing pin diameter.

 

[1000yardstare]

Twenty years ago, had a custom 6/250 rifle made up on a Rem 722 action for 300 metre ISU competiton, sling, aperture sights. Worked up loads in May which in Ontario would average around 18C,64F). In August, went to a 300 metre competition on a Canadian Army range which is essentially a big open field with firing mounds, no shade. The temp was around 30C,86F) when we started firing. The bolt opened hard on the first round, had to pound the bolt open with my palm on the second shot. The third shot blew a primer and the bolt was frozen shut. Guess the combo of air temperature, direct sun on the ammo box and hot chamber steel sealed the deal. Had to withdraw from the competition. Back home, used a wooden mallet to tap the bolt open. No permanent damage. A painful lesson. Now I load Summer match rounds at least a grain lower than Spring practise rounds and try to keep the ammo box in some sort of shade on the firing line during a hot summer day.

 

[cliffy]

Minor primer cratering merely indicates a maximum pressure condition. When no cratering exists, one is not even close to maximum pressure loads. A little cratering indicates you're THERE! Bursting through a primer,piercing a primer), says you are running too hot powders chargewise or you have selected inadequate primers for the desired results. I've run this gauntlet, especially concerning small rifle primers. Small rifle .223 Remington primers seem MOST sensitive to this min/max scenario. CCI 400 primers were never created for .223 Remington application. These fine .22 Hornet, .219 Zipper, and .218 Bee PRIMERS work well within application. A beast of a 3000+ fps .223 Remington load leaves these specific primers in the dust of AR-15 horsepower. This is where CCI 450 and MAGTECH 7 1/2 and most other 7 1/2 Magnum primers were designed to excel. Before blaming the desired load, blame the chosen primer. cliffy

 

[AckleymanII]

Glocksig, you have an oversize firing pin hole in your bolt, get if fixed, best money that you will ever spend.

One other thought, brass flows on a 243 from shoulder into the neck. You may start to have a doughnut starting to form right in the base of the neck that is causing a pressure spike...check it out.

Your load is one that I have shot for many years in custom and factory 700's with 80g Sierra BT Blitz, amazing accuracy.

I recently switched to 42.3g of Hogdon HV100 with a Win primer with the 80's and cut my groups in half at 300 yards with the 80's, mine is a hunting rifle, also. Pressure did not have the spikes that the 4064 had, maybe give the Hv100 a try with the Win primers with the 80's.

Don't forget to get that bolt bushed...you do have an issue that will hamper you in getting the most from your 243.

Good luck!

PS. Primer cratering is no indication of pressure when you have the huge clearance around the firing pin hole that allows the metal to flow at lower pressures.