Strange occurrence at the range today with handloads

[Oldschool280]

Today i tried a new load for my .257 weatherby vanguard. I have loaded for and shot this rifle with fantastic results in the past using other powders. Todays new load was using w760 powder and barnes older 80 grain tsx. I used a starting load of 64 grains of powder. This was data i took from the nosler book for their 85 grain. I also checked a few other places online and found info regarding 80-85 grain projectiles that also put the starting charge at 64grains. I then compared barnes load data for other powders and compared to other bullet manufacturers recommendations for matching powders and all seemed to agree. Well, the first round acted like a hang fire. Just a slight delay. Then a large bark and a hole rigjt where i was aiming, all was fine till time to
Lift the bolt. Super hard bolt lift, primer blown out, extractor marks. All signs of high pressure correct? The front of the case was dented in multiple places like an underpressure load , and here's the kicker, the neck didnt expand. It is as tight as if it went through the sizing die. Remember this is a weatherby with lots of freebore and a short bullet. Nowhere near the lands. After that round i tried a load that always shot well in the rifle with rl25 powder and click. No detonation, open bolt take a look and no mark on primer. I think the firing pin took a beating, the headspace seems ok . What the hell happened? Going to check it more thoroughly tomorrow. Thanx in advance for replies and thoughts.

 

[26Reload]

Reads like you came close to blowing your face off....
....how was powder fill %.....
....best pull the bolt apart and inspect parts and pieces....maybe a small chunk of the first primer got inside the firing pin hole.....

 

[Calvin45]

Reads like you came close to blowing your face off....
....how was powder fill %.....
....best pull the bolt apart and inspect parts and pieces....maybe a small chunk of the first primer got inside the firing pin hole.....

It's this. I'm certain. I have a weatherby vanguard in 257 that has done this when I got stupid and stepped on the gas too hard. Ever since the seized bolt inducing round that pierced the primer, it would fire erratically, sometimes fine, sometimes not at all, sometimes a light primer strike…

Took the bolt apart and indeed there was a perfect little circle of primer cup metal inside the firing pin hole.

Be careful.

I hate w760 for a reason haha, would never have even thought to use it in the .257 bee.

 

[MagnumManiac]

Bad powder choice for a very low starting charge…this is called detonation, powder starts then stalls then ignites all at once. Have seen this on the Pressure Trace, muzzle pressure often exceeds 100,000psi! Be careful with solid copper/brass bullets and difficult to ignite ball powders.

Cheers.

 

[Dean2]

What you had was a Click-Boom. There are a number of potential causes, too weak a primer, as in using a CCI 250 instead of a Fed 215, big issue with large capacity cases using hard to ignite powder, or too small a fill percentage causing a powder position issue, or too low a powder charge for the case capacity. Any one of these can cause some serious problems because what you end up with is a poor ignition of the powder, as in it starts to light off, but doesn't fully light all at one time, and this results in the bullet staying in place far longer than it should, generating a large pressure spike. In its worst form you will find the the round doesn't go off at all but the primer has gone off and the powder is lumpy and a hard mass inside the case, almost like it melted then hardened, which is what it actually did.

My last comment, though not what you did, under loading or trying to make reduced recoil loads for over capacity cases like the 7 RUM, 257 Bee etc is a bad idea as this can also cause detonation, which results in the same pressure spike..

 

[Oldschool280]

Reads like you came close to blowing your face off....
....how was powder fill %.....
....best pull the bolt apart and inspect parts and pieces....maybe a small chunk of the first primer got inside the firing pin hole.....

Yikes! Thanx for the reply. Percentage of fill was certainly lower than the rl 22,25 loads i use. There was metal in the bolt.

 

[kiwikid]

Yikes! Thanx for the reply. Percentage of fill was certainly lower than the rl 22,25 loads i use. There was metal in the bolt.

After reading the OP I looked through several reloading manuals to see how @Oldschool280 load compared. As stated the Nosler 9th manual lists 64 grains of Win 760 as the start load with a max of 68 grains for their 85 gr BT. The start load is 79% case full.
Hornady 10th manual lists 55.6 grain as a start load with a max of 61.2 gr for their 87 gr SP.
The older Speer 10th edition manual (1980) lists a start load of 63 gr and a max of 67 gr for their 87 gr Spitzer.
If the Nosler load is possibly a recipe for a detonation it is a good thing he didn't take his load info from the Hornady manual. Yes I do realise he was loading the 80 gr TSX and neither an 85 or 87 grain bullet.

 

[Rick Richard]

Don't know about the load and what happened, but you're going to have to replace the firing pin spring for sure. Don't ask me how I know this….but now you know.

 

[Reelamin]

Probably pushed the little primer disk back into firing pin hole locking or blocking firing pin. You were long ways from blowing any body parts off just an over pressure load.
Clean out the bolt and everything will be fine.

 

[Flatbow]

Wow,
Thanks for sharing as this is good to know.
I load for several large rounds including my 7RUM knowing that I did not want to use a powder that did not have a good case fill rate for consistency but did not know it could cause this.
I have learned a ton about reloading on This sight over the years.

 

[Seabeeken]

I hate w760 for a reason haha, would never have even thought to use it in the .257 bee.

^^^^^THIS
I had crazy unpredictable pressure spikes with W-760/H-414 in my 243 AI during load workups. I have not and never will use it again.

 

[birddog 68]

^^^^^THIS
I had crazy unpredictable pressure spikes with W-760/H-414 in my 243 AI during load workups. I have not and never will use it again.

Very interesting. I used W760 for years in my 7-08 and never had any problems but case fill was very good compared to a 257 bee. I usually pick a powder that has at least 90% fill but 95-100% is better imo.

 

[Muddyboots]

If you use W760 within load data, it is a fine powder. Any ball powder used in application without data can be interesting due to low case fill.

W760 is a fast powder for this load in comparison to Barnes data which prob contributed a lot.

 

[Seabeeken]

Very interesting. I used W760 for years in my 7-08 and never had any problems but case fill was very good compared to a 257 bee. I usually pick a powder that has at least 90% fill but 95-100% is better imo.

I used it for years in a 7RM without issue. In my 243AI pressure would be normal and then stiff bolt and pressure signs from the same load. The next heavier charge would be fine again. These were not reduced loads so I doubt it was a detonation issue. Rifle acted fine with a number of other powders I tested