headspace issues?

[Tnslim]

Rifle is a Stevens action, CBI 28" bull in 6BR, bedded in a Bobby Hart stock. Fired for the first time yesterday and got some extractor marks on the brass and also a shiny spot on the extractor. It was a bit stiff chambering a new round. I loaded Sierra 107 in new Lapua brass at .020 from lands. When setting headspace I used a go-gauge and I measured a piece of scotch tape at .002 thickness and used that on the rear of the go-gauge. When closing the bolt with the taped go-gauge the bolt would go no farther than the 1 or 2 oclock position. Do I have insufficient headspace that would cause this problem? Thanks.

[82boy]

Rifle is a Stevens action, CBI 28" bull in 6BR, bedded in a Bobby Hart stock. Fired for the first time yesterday and got some extractor marks on the brass and also a shiny spot on the extractor. Do I have insufficient headspace that would cause this problem? Thanks.


Sounds like headspace is fine, the load was a bit too hot.

[stangfish]

Try an empty case, if it closes like the go gauge then you are into the lands with your loaded cartridge. Back off until the bolt closes easily...or if it is snug with an empty brass then you need to move your headspace back .002 more if you are yousing a neck sizer die, and if you are full length sizing you may want to measure the headspace on the case and compare it to your gauge. Then bump it back a few thousandths at a time until it fits the chamber if/as needed. Post results.

[Tnslim]

82Boy, the load was 30.0 gr Varget and 107 Sierra's, CCI450 primers, neck sized with temp around 60*. Primers looked fine showing no signs of a heavy load, the only mark was the extractor spot. These were the breaking in shots and it's very possible that was too hot to start with. Probably should have started out with lighter loads.

Stang, I'll do the empty case deal and see how that goes. When I final assembled the rifle I screwed the barrel to just touch the go-gauge and backed it off a fine hair then snugged the nut. Put tape on gauge and bolt would just barely start down but would chamber fine without the tape.

[82boy]

82Boy, the load was 30.0 gr Varget and 107 Sierra's, CCI450 primers, neck sized with temp around 60*. Primers looked fine showing no signs of a heavy load, the only mark was the extractor spot.

YUP that is it, 30Gr of varget is on the hot side of things. I would say that varget is the worse powder as far as varience from lot to lot. With that said some lots are a TON hotter than others. I have seen one lot of varget that would be fine at 30gr, and the next lot would be WAY TOO HOT, at 30 grs. If your getting an ejector mark you are having pressure problems, back it off a couple of grains and see what happens.

[earl39]

I would say that varget is the worse powder as far as varience from lot to lot. With that said some lots are a TON hotter than others. I have seen one lot of varget that would be fine at 30gr, and the next lot would be WAY TOO HOT, at 30 grs.

And that is why i dont use Varget any more.

[stangfish]

This is what got my attention. And these fellas know alot more than I do..........


It was a bit stiff chambering a new round.

[handirifle]

While I will not dispute the findings of others, I have used Varget quite a bit with none of the mentioned issues. What I have found WILL make a huge difference in pressures, from load to load, is the use of different brands of brass, loaded with the same charges of powder, any powder.

Some cases are thicker inside than others and will GREATLY increase pressures. That is ONE of the reasons the 5.56 ammo loads are hotter than factory 223 loads, thicker brass for more reliability in the battlefield. That is why all the manuals say to start at starting load levels and work up. A safe load for one brand of brass isn't safe for all brands of brass.

[Tnslim]

Ok, I finally got back to this rifle again and tried chambering an unfired case. It was a bit stiff and basically had to slam the bolt home to chamber either new brass or once fired brass. I checked the headspace again with the PTG go-gauge and it felt fine and with a piece of measured .002 tape the bolt would just barely move downwards. If I give it another .002" headspace what could it hurt and do you think it would help?

[jonbearman]

Sounds like it is time for a chamber cast to make sure the neck area of the chamber is on the tight side.If it is where it is rubbing(mark it up with dry erase marker and try closing it and extract it and note where the tight spot is) you may have to turn your necks to just clean up the surface.You shouldnt have to remove anymore than half a thousndths. You might measure overall length and full length size one case,if it doesnt fit,try setting the die to cause cam over on your press and try chambering again,if it doesnt go easy,you may have to send the barrel to someone to inspect it,because from what I have read,it sounds like you set the headspace right on.Now hows that for a run-on sentence.LOL PM me for help if you need it.

[handirifle]

Are these all reloaded cases? Have you ever tried factory ammo in it? I suspect your dies may be incorrectly adjusted. As was suggested earlier, try setting the fl size die down a 1/4 turn and see how the empty brass chambers. If thats fine then try a NEWLY SIZED Loaded cartridge.

[ellobo]

+1 on handirifles suggestion.

El Lobo

[Tnslim]

I don't have any factory ammo to check with as I rarely use the factory stuff and I neck size with Forster dies. I'll set up my full size dies this evening and try again. I'll search the house for a dry erase marker and chamber a couple rounds and see if that shows anything. Thanks for the help and I'll post the results.

[Tnslim]

I could only finds a permanent marker but it showed no scratches. I miked the necks, here's the following sizes.
new unfired neck.. .266
new neck sized .. .266
once fired unsized .272
once fired necked .266
new length 1.554
once fired length 1.557

I'm using Forster dies (neck sizer) that to start with would leave scratches the length of the neck to shoulder. I sent them back and they charged me $27.00 to hone/polish but I still get scratches but not as deep. When I close the bolt to battery w/o brass it closes just fine. If I chamber any brass, new or once fired, sized or not the last 1/8" is hard to close the bolt. I have to use force and speed to close the bolt with any brass. I haven't re-adjusted the headspace yet but think that should be my next step. My patience and hair are both getting thin. I'm not happy with these Forester dies but don't really think that's my problem as the bolt is hard to close with new unsized brass.

[Dennis]

new unfired neck.. .266
new neck sized .. .266
once fired unsized .272
once fired necked .266
new length 1.554
once fired length 1.557

I don't have any loaded 6br's.

But . . .

My once fired unsized avg .270
new neck sized is avg .268-new cardboard brass
new length 1.556
once fired length 1.558

Still looks good here!


When setting headspace I used a go-gauge and I measured a piece of scotch tape at .002 thickness and used that on the rear of the go-gauge. When closing the bolt with the taped go-gauge the bolt would go no farther than the 1 or 2 oclock position.

Perfect, exactly how I installed mine, this should not be a problem!


the only mark was the extractor spot

I have a 6.5x47L and had similiar issues! I back off the powder charge. Everybody else was using almost a grain more powder than I! I ruined a lot of brass in the process, when I backed off my charge, the gun started driving nails and I had no brass issues, no sticky bolt, no issues at all. Nobody can explain why this gun is this way! I might add I have never got it to shoot heavy bullets, 139-140-142's, it will shoot 130 decent. But 120 and 123's, the job gets done.

It makes me wonder when I see everybody else shooting heavier bullets and doing good, I try, I go home and I unload rounds because there too HOT. I have talked to one other person who has the "same" issue with his 6.5x47L! We both have tried everything but come up with the same results.

Anyway, back to your BR, try backing off to 24.2 and working up .2grns to 24.8 and see what happens. Every gun is different. You might try RL 15 or something else. My BR is good with 24.8grns Varget shooting 107SMK's, but again, start low and let us know what happens! .020 off should be fine, Mine likes to kiss the lands with the 107's.

[Tnslim]

Well, my plan was to load up my portable reloading rig and shooting table but it's pouring rain as we speak with snow on the way and it takes 4wd to get to my cow pasture shooting range on a sunny day. Not much flat ground in east Tennessee. I made a stupid mistake on the extractor mark as the marks are coming from the bolt head where I removed the ejector, not the extractor. Also, the hard last 1/8" on closing the bolt was where the extractor has to slip over the case rim. I have done the larger extractor ball swap and just swapped back to the smaller ball with no difference noticed. When I fit a fired case under the extractor and close the bolt it chambers much easier but the bolt closing and bolt lift are still fairly stiff. I also noticed the brass has what looks like slide marks on the head caused by the ejector hole as I could see some fine brass dust in the hole. I'm still leaning towards insufficient headspace but being an old rookie I am still open for suggestions.

[KRP]

It sounds to me like your load is too hot, as has been mentioned...more than once.

Maybe not though, if someone can explain how "insufficient" headspace could cause these symptoms?

[stangfish]

Maybe not though, if someone can explain how "insufficient" headspace could cause these symptoms?

The statement below caught my attention. Difficulty chambering an unfired case can mean that the case headspace is too long making it difficult to chamber the round. This has stood out since the begining. I personaly think his situation could actualy be a combination of case headspace length and hot load.



Ok, I finally got back to this rifle again and tried chambering an unfired case. It was a bit stiff and basically had to slam the bolt home to chamber either new brass or once fired brass. I checked the headspace again with the PTG go-gauge and it felt fine and with a piece of measured .002 tape the bolt would just barely move downwards.


I hope this sheds light on why there is the potential for a case headspace length issue. As for extraction, presure is always a primary cause.

[Baryngyl]

Also, the hard last 1/8" on closing the bolt was where the extractor has to slip over the case rim.

I had the same problem with a new extractor, it got a lot easier after I smoothed the extractor angle with a file.

Michael Grace

[Tnslim]

I took the advice of another site that specializes in 6BR who recommended starting at 30gr Varget with the Sierra 107"s and in hindsight I probably should have started out lower. I fired 29 rds at 30gr doing the fire one and clean for the first 10 shots then cleaned after every 3 shot group. The primers looked perfect plus the groups were ok so I didn't suspect a hot load. My concern was with stiff chambering and equally stiff extraction. I know that a too hot load will sometimes make it hard to extract but it shouldn't affect chambering which made me suspect headspace. The bolt handle had quite a bit of drag when closing to battery making me feel the headspace was too tight, but again, I'm a rookie at this.

On another note, the Criterion barrel is the easiest to clean I've ever seen plus I'm pleased with the accuracy.