Pressure Issues ?

[timeout]

I have a question regarding causes for pressure issues. A friend of mine is experiencing pressure signs not limited to, but including, hard bolt lift, stuck cases and ejector marks. This is happening with a 6 Dasher at anything above 30.0 grains of Reloader 15, Berger 105's .010" away from the lands, Rem. 7 1/2 primers and Lapua fire formed brass. The action is a Remington 700 previously built as a complete 6BR by GreTan. The barrel is a Krieger 1 in 8 twist, #3 contour. I have 4 Dashers using both Krieger and Brux barrels, Rem. 700 actions and one Panda action (all 1 in 8 twist shooting 105 Bergers and Reloader 15). My friend has two Dashers with 3 different barrels, a Rem 700 action and a Stiller action. I personally am shooting the same components in my Dashers and using the following charges of Reloader 15 with no pressure issues: 32.5 gr., 33.8 gr. and 34.3 gr. All loads were worked up starting low and working up .3 of a grain while performing ladder tests. All barrels have been chambered with the same reamer. Three of the barrels have been throated longer using a PTG unithroater. This particular barrel has not yet been throated beyond the .104" freebore the reamer provides. The cases are well under maximum length, fired neck diameters are correct giving proper clearance for bullet release. The barrel has been properly cleaned to remove copper fouling. The rifle has not been fired enough that a carbon ring in front of the neck could be problematic. The brass has been previously fireformed, not initial 6 BR brass. Throating to seat the bullet out farther may allow a bit of additional powder charge before pressure signs, but I am doubting it would bring the loading up to even 33 gr. of Reloader 15? This is a new barrel that exhibited the high pressure signs from the get-go. By a process of elimination, I feel that the barrel must have issues. I'm looking for any ideas on something else we have have missed prior to contacting the folks at Krieger. Your insight to this matter is greatly appreciated!

 

[joshb]

Just from my reading, here,as I'm just starting. Could it be a tight bore?

 

[22BRGUY]

Would maybe do a chamber/throat/barrel cast with cerro-safe and measure bore diameter and also actual bullet diameter.

Best Wishes

 

[wedgy]

What velocity were you getting compared to the other barrels ?

 

[timeout]

What velocity were you getting compared to the other barrels ?

I spoke with him yesterday and he had not put the magneto speed on it. At under 30 grains, he did not feel it was worth checking. I don't think that I can get an answer on that until the weekend.

 

[Ggmac]

Check accuracy , check velocity . I have a feeling the vel will be at or near yours . Pressure USUALLY equates to velocity . If he's using same lot of powder and same cases , not reformed from 308 or 30-06 or 243 cases , you get the idea , same case capacity .

 

[timeout]

He says accuracy sucks. All other barrels have shot well.

 

[bsumoba]

I'm going to go with a tight bore.

My next is you have a HOT lot of RE-15.

 

[timeout]

I'm going to go with a tight bore.

My next is you have a HOT lot of RE-15.

I'm thinking tight bore also. Same lot of Reloader 15 being used in the Stiller and a Rem. 700 with a different barrel ( 5 lb. jug) Just wondering if we are forgetting anything else? Thanks!

 

[Ggmac]

A tight barrel should have shown up when chambered , if the smith did his part . What about cases , the same that are being used in yours or other barrels ?

 

[timeout]

Yes, same cases.

 

[bsumoba]

Maybe you can check the volume of H2O in the brass getting pressure signs? Maybe that brass is just thicker in the body area, making for a smaller case volume?

Another thing I was thinking is maybe the bullets are "thicker"? Maybe measure both to make sure they are all in line with "standard" specs.

 

[CaptainMal]

Reloader 15, like Varget, is DIRTY. Your friend may not be scrubbing with Iosso and C4 carbon cleaner. That carbon stuff builds up in the whole bore, in addition to the area in front of the chamber.

Get a look at it with a borescope and/or scrub, scrub, scrub, scrub ...

Then scrub some more. It can take very few rounds for the problem to begin.

I had the same issue with my last barrel. I know what trouble a Dasher can be when the bore fouls. I know. Oh lord I know.