12 fv bolt opens part way, infrequently

[Robinhood]

You are right. I did not see the 26" data. It may be relevant. And just so the forum knows. I am humbled by your research. It is exhaustive. Almost scary the amount of time you must have put in. It would have been easy for you to copy and paste it so I took what I saw and offered it below.

The problem is regardless of how much data you have, in this rifle, the load is flawed. If the PE ramp is making any contact whatsoever, it is not helping. The fact you are using a mallet to open the bolt says the pressure is high. A mallet Joe. Think about that for a moment. You have justified using oil to help case extraction. Think about that for a moment. You think making a larger primer hole is an answer all while potentially making this even more dangerous. You have subscribed to proven faulty pressure sign indicators. You have also subscribed to accuracy and speed has negated the pressure issue. I admire the dedication but warn that sometimes it becomes an obsession.

Now that this horse has been beat to death multiple times how about a different paradigm.

What drives this effort?
What are the goals/purpose?
Is there a specific projectile?
A desired velocity?
A desired terminal performance?
Can another cartridge be used?

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ALL 22-250, 100 YARD 5-SHOT GROUPS
ALL WITH WEAVER T36 SCOPE.
8.5 GR. SEEMS TO BE THE MOST ACCURATE TITEGROUP CHARGE.
THESE ARE THE LATEST AND BEST GROUPS.

M11 BARREL CUT TO 16.5”, 12” TWIST? IN STRIKER PISTOL ACTION AND STOCK

5/10/17, 225646M, 8.5 GR. TITEGROUP, 6 GROUPS AVG 1.304”
5/15/17, 225646M, 8.5 GR. TITEGROUP,11 GROUPS AVG 1.350”
5/17/17, 225646M, 8.5 GR. TITEGROUP,13 GROUPS AVG 1.648”
30 GROUPS AVERAGE 1.470”

5/10/17, 40 GR NOSLER VARMAGEDDON, 8.5 TITEGROUP, 5 GROUPS AVG .780”

M11 BARREL CUT TO 16.5”, 12” TWIST?, IN M 10 ACTION AND RIFLE STOCK

5/22/17, 225646M, 8.5 GR. TITEGROUP,5 GROUPS AVG 1.360”
5/31/17, 225646M, 8.5 GR. TITEGROUP, 5 GROUPS AVG 1.385”
6/22/17, 225646M, 8.5 GR. TITEGROUP, 5 GROUPS AVG 1.570”
10 GROUPS AVERAGE 1.440”

5/22/17, 40 GR NOSLER VARMAGEDDON, 8.5 GR. TITEGROUP, 2 GROUPS AVG .925
5/31/17, 40 GR NOSLER VARMAGEDDON, 8.5 GR. TITEGROUP, 5 GROUPS AVG .815”
5/31/17, 40 GR NOSLER VARMAGEDDON, 8.5 GR. TITEGROUP, 5 GROUPS AVG .755”
12 GROUPS AVERAGE .808”

M110 BARREL, RECHAMBERED FROM 223 TO 22-250, CUT TO 16.5”, 12”
TWIST?, IN STRIKER PISTOL ACTION AND STOCK

3/20/17, 225646M, 7.5 GR. TITEGROUP, 5 GROUPS AVG 1.310”
3/23/17, 225646M, 75 GR. TITEGROUP, 5 GROUPS AVG 1.450”
3/25/17, 225646M, 7.5 GR. TITEGROUP, 5 GROUPS AVG 1.680”
15 GROUPS AVERAGE 1.480”

3/27/17, 40 GR NOSLER VARMAGEDDON, 7.5 GR. TITEGROUP, 3 GROUPS AVG .867”

BLUE STRIKER BARREL, 14” TWIST?

2/27/17, 225646M, 8.5 GR. TITEGROUP, 5 GROUPS AVG 1.185”
3/8/17, 225646M, 8.5 GR. TITEGROUP, 5 GROUPS AVG 1.405”
3/8/17, 225646M, 8.5 GR. TITEGROUP, 5 GROUPS AVG 1.440”
15 GROUPS AVERAGE 1.343”

4/24/17, 40 GR NOSLER VARMAGEDDON, 8.5 GR. TITEGROUP, 3 GROUPS AVG 1.067”
5/1/17, 40 GR NOSLER VARMAGEDDON, 7.5 GR. TITEGROUP, 5 GROUPS AVG .945”
8 GROUPS AVERAGE .991”



SS STRIKER BARREL, 14” TWIST?

3/29/17, 225646M, 8.5 GR. TITEGROUP, 5 GROUPS AVG 1.531”
3/31/17, 225646M, 8.5 GR. TITEGROUP, 2 GROUPS AVG 1.988”
4/3/17, 225646M, 8.5 GR. TITEGROUP, 4 GROUPS AVG 1.150”
4/3/17, 225646M, 8.5 GR. TITEGROUP, 5 GROUPS AVG 1.400”
4/5/17, 225646M, 8.5 GR. TITEGROUP, 6 GROUPS AVG 1.413”
22 GROUPS AVERAGE 1.441”

12/5/16, 40 GR NOSLER VARMAGEDDON, 7.0 GR. TITEGROUP, 3 GROUPS AVG .850”
12/26/16, 40 GR NOSLER VARMAGEDDON, 7.0 GR. TITEGROUP, 4 GROUPS AVG 1.313”
4/7/17, 40 GR NOSLER VARMAGEDDON, 8.5 GR. TITEGROUP, 4 GROUPS AVG .894”
11 GROUPS AVERAGE 1.029”

NEW SHILEN BARREL, 9” TWIST? IN SAVAGE 12FV ACTION AND STOCK

I’VE BEEN SHOOTING THIS BARREL SINCE JANUARY 2017; BELOW ARE THE LATEST AND BEST RESULTS SO FAR.

6/15/17, 225646M, 8.5 GR. TITEGROUP, 4 GROUPS AVG 2.438” AFTER 34 FOULING SHOTS

6/15/17, 40 GR NOSLER VARMAGEDDON, 8.5 GR. TITEGROUP, 2 GROUPS AVG 1.275” AFTER 54 CAST BULLET SHOTS

6/26/17, 40 GR NOSLER VARMAGEDDON, 8.5 GR. TITEGROUP, 5 GROUPS AVG 1.225”

6/26/17, 50 GR HORNADY V-MAX #2261, 8.5 GR. TITEGROUP, 2 GROUPS AVG 1.150”

6/26/17, 60 GR HORNADY SP #2271, 8.5 GR. TITEGROUP, 2 GROUPS AVG .800”

6/26/17, 68 GR HORNADY BTHP #2261, 8.5 GR. TITEGROUP, 2 GROUPS AVG 1.075”
ALL 40, 50, 60 AND 68 GR BULLETS; NO TIPPING.

THE AVERAGE FOR THE DAY, 55 SHOTS, 11 5-SHOT GROUPS, 4 BULLETS, 1.107”.

AFTER 60 JACKETED SHOTS, THE CLEANED BARREL, SOAKED WITH HOPPES #9 OVERNIGHT, SHOWED NO SIGNS OF BLUE/GREEN COPPER FOULING.

[Robinhood]

Joe, you never told us if the oil you have been using has gummed up the chamber. Have you tried to clean it if so? What method did you use to clean?

[joeb33050]

I was changing bbls on M10 and Striker this AM, Striker cases with >.004" excess headspace and bolt Resists at PE, >.005" and a lotta resistance. It's case length/primer protrusion that caused the problem.
Thanks;
joe b.

[Robinhood]

Was headspace set with a go and no go gauge or were you over sizing the brass? Was the primer protrusion an issue or was it an indicator of the chamber brass length issue? Glad you got it figured out.

[OLEJOE]

Hell, what do the manufacturers know about this stuff, anyway? Overbore means slower​ powders than would be used in a .223 or .22 BR
Recommended burn rate in the H4895 range (89) , Titegroup (15)...

I'd be pulling that trigger with a string from ten feet away.
^^^ Behind a tree or bunker.

[joeb33050]

Was headspace set with a go and no go gauge or were you over sizing the brass? Was the primer protrusion an issue or was it an indicator of the chamber brass length issue? Glad you got it figured out.
I set headspace with fired cases measured with RCBS Precision Mics. I can adjust case headspace to +/-.001", chamber/bolt headspace to ~+/-.002".

[joeb33050]

^^^ Behind a tree or bunker.

Monday I fired 54 total shots; Nosler 40 gr, Titegroup, 100 yards, five 5 shot group averages. 8 gr., .685" avg, 8.5 gr.,.740" avg. So far I've recorded groups totaling 2975 shots, all low velocity, almost all Titegroup, and nary a single occurance of a pressure indication or spike. Imaginary?

[Robinhood]

How are the 7.5 loads working. That was the powder weight you originally stated that was giving you problems. I have had pressure spikes from low Trailboss loads in the 223.

Have you ever used a pressure trace. They are cheap.

The article I posted higher up states that high pressure does not always manifest itself in the ways you mention. It can't hurt. Read it for edification.