Pressure signs way below max load

[antelopedundee]

Thank you.
I forgot to mention that I am very conscious about my loads, I use the RCBS Chargemaster Lite in conjunction with the RCBS beam and myweigh 300 II for every load. judging by the amount of research done and how anal I am with my scales I doubt powder weight inaccuracy is the issue. A fellow shooter has an autotrycler i should check my scales against his who knows maybe all 3 are broke or even something within my environment that i missed ...
I thought that maybe there is something with the chamber or the rifle itself that cause this behaviour ...

Why not just weigh a bullet to see if your scales might be off?

 

[Lycanit]

Just wanted to clarify the pressure signs you're seeing I related to the primers? No stiff bolt lift, bolt head swipes, separation ring? any of that stuff correct? There's just so many pages on this it sometimes hard to keep up

 

[Mc Fraser]

Just wanted to clarify the pressure signs you're seeing I related to the primers? No stiff bolt lift, bolt head swipes, separation ring? any of that stuff correct? There's just so many pages on this it sometimes hard to keep up

This is what I see. From left to right min, medium and max powder weight. This iPhone can't take really good pics but all 3 cases have pressure signed on primers. The case
on the right I believe has a pressure sign after mag

 

[Mc Fraser]

Why not just weigh a bullet to see if your scales might be off?

I'm using 3 scales. None of them is out.

 

[lancetkenyon]

OK, I have not read this whole thread. I followed along at the begininng however. Seems like most of the usual culprits have been suggested. I will add one more.

I have a buddy who built a custom 6.5SS. I have two of the same, built by the same gunsmith with the same reamer. I have also loaded for other 6.5SS by the same gunsmith who used the same reamer. Now my buddy had a 22" Proof Sendero on his, amd my two are Bartlein 25.5" & Proof 26" respectively.
He had tried about every powder we suggested. H1000, H4831, RL23, RL26, N565, Retumbo....nothing would get him speeds within 250fps of any other 6.5SS I have heard of without pressure signs. Accuracy was decent, but not spectacular either.
He contacted the smith, he contacted Rich, we talked weekly about it, he sent me fired and FL sized brass to measure against both mine (they were identical in every way), I FL sized them in my dies, I ran them through my expanding mandrel, We tried everything. To no avail.

Well, he got so frustrated with it, he took it back to the smith at least 3 times. Finally, after a few hundred rounds of chasing the issue, another bore scoping was done, and they thought they just might see a spot in the bore that looked a bit different. The barrel was pulled and sent back to Proof. Low and behold, he had a bad barrel. A swell was halfway down the bore, which was causing issues. He got that one in 10k barrel. Proof is sending out a new barrel, ad I am waiting to hear if they are doing anything else to help out.

So, you very well could have a barrel issue going on.

 

[Lycanit]

Anything mechanical has a failure rate. No matter how small.

 

[Orange Dust]

This is what I see. From left to right min, medium and max powder weight. This iPhone can't take really good pics but all 3 cases have pressure signed on primers. The case
on the right I believe has a pressure sign after mag

Hard to tell from the pict but it looks like there is an extractor mark on the case on the right. Sure sign of overpressure. Primers aren't really a good indicator of pressure unless you know the rifle well. Have you miked the case before and after firing? You have to use a micrometer not calipers. Some measure the rim, some measure the belt, and some just in front of the belt. To each his own, but ANY measureable dif on the rim is too much. So is .001 on the belt. Extractor marks are a reliable measure of over pressure for the lot of brass you are using. Bushing the firing pin will not change these.

 

[Mc Fraser]

The plan is to do the bushing on the bolt, then fire it again (I'm using Forester micrometre and shoulder bump dies), if it doesn't work inspect the barrel, if nothing is seen, cut the barrel to 26in and try again (although I'm not convinced that a longer barrel adds pressure when everything else is equal).

 

[Orange Dust]

The plan is to do the bushing on the bolt, then fire it again (I'm using Forester micrometre and shoulder bump dies), if it doesn't work inspect the barrel, if nothing is seen, cut the barrel to 26in and try again (although I'm not convinced that a longer barrel adds pressure when everything else is equal).

Me either.

 

[Orange Dust]

Actually, I wouldn't cut the barrel or worry about what your load is vs recommended max. You are seeing RUM velocities. What are you hoping for to obtain with a WM? I would be excited and looking for ways to lower ES. You have found max. Hunt your best load.

 

[Mc Fraser]

It was the hole on the bolt, smith put a bushing on it and now it shoots like before.
Ladder test looks promising with 200gr ELD-X. I'll keep you posted.

 

[skipglo]

Ladies and Gents,
I have a Win M70 in 300 win mag that has a 29in Krieger barrel with a brake and glass bedding done by a reputable gunsmith.
I understand how min and max loads from reloading books work, however beyond that could you think at any other reason why I see pressure signs below max load. I use Norma brass new and fire formed and I constantly see pressure signs 1.5 to 2.5 grain below max load with with different powders and bullets. H1000 imr 7828ssc, retumbo

What grain of bullets and what's your COAL..
Seating depth makes a huge difference

 

[Mc Fraser]

What grain of bullets and what's your COAL..
Seating depth makes a huge difference

It was the hole on the bolt, smith put a bushing on it and now it shoots like before.

 

[skipglo]

It was the hole on the bolt, smith put a bushing on it and now it shoots like before.

Excellent....great to be up and running!
.