6.5x55ai problems...

[slingworks]

I have a rem 700 with a heavy 6.5x55ai barrel by Benjamin, w/29" barrel 1-8" twist.
The barrel is new, we've fired less than 200rds...
Seems to have some problem, rifle blows primers right and left, even on light loads...
I am using 44gr of H380 and 140gr Sierra HPBT Match bullets.....Accuracy is outright horrible.....5-8moa!!!
44gr of H380 is a very light load for anything, so I know that the powder, charge, bullet, cases, etc are not the problem..
This rifle should shoot .25moa, I have AR rifles that shoot .25-.50 moa!!
Is it possible the barrel is bored undersized???!!! What can make such pressure problems on such a light load??! Anyone have problems with Benjamin 6.5 cal barrels??

 

[Eddie Harren]

Anytime I hear about pressure signs, on AI cartridges, I have to wonder about the heardspace issue. How are you sizing your brass? How far are you setting the shoulder back? Does the blown primer situation occur with reloads or, only on fireforming loads?

 

[slingworks]

Thanks for the reply!

I am resizing with special order RCBS AI 6.5x55 dies, and trimming to length.
the chambering in the barrel is a good one, and feels just right when we close the bolt into battery...

the primer blowing is serious, and we've used Norma, RP, Win, Serb, just about every make brass I can think of and still the same problem...And none are worn out.

Yesterday when it blew primers it cut a pretty deep gas ring on the bolt face.
I dont think I ever encountered than on a Rem 700.....

 

[Eddie Harren]

Sorry I can't help you. If the headspace is correct and you're not setting the shoulders back too far I have no idea. You didn't answer my question about how far back you're bumping the shoulder nor did you let me know if it was only when fireforming. Blown primers and hot loads will surely cut a ring in the boltface.

 

[15Tango]

Slug that barrel to make sure it's not .257", that's the only thing I can think of.

Wayne

 

[1000yardstare]

Not trying to be insulting but are you sure that the powder is H380? A buddy of mine accidentally dumped some AA2460 into a container of AA2520 and almost destroyed a rifle. Took him a while to figure out what was happening.

 

[LHSmith]

Check FP protrusion. H380 is too fast for this chambering.

 

[jonbearman]

do you leave sizing grease on your brass,definitely check the actual bore size and you dont need to slug it to see that much difference if it is way undersize.Just measure with calipers gently as not to scratch the crown.Second I would get a different pound of powder to try,if the h380 doesnt look like siver tiny bb's the size of sand then something is way wrong.I would try a whole different powder for trials and load it real mild.The other thing that comes to mind is the sizing die,if it undersizes the brass then you are not feeling the shoulder contact but the body contact and that could be a false indicator. Meaning you arent headspacing on the shoulder but the body.Are you using a headspace gage? If you just size a case that can be catastrophic if it is sized wrong,again a bad die possibly.

 

[jonbearman]

There is no listing for the powder you are listing for 140 grain bullets.The only listing is for a 110 grain bullet in the hodgen manual.I would think h4831 or aa3100 or imr7828 ,where are you getting your imfo from? You just made a serious error.If it came out of a book is the book older than the hills or what.You are really lucky you didnt blow the gun up and take your hand and face off.Which book are you using? I dont want anyone to get injured having fun.

 

[slingworks]

Thanks for the advice men.

Actually I generally use Reloader22 in my standard 6.5x55 cases, we decided to use the H380 in the 6.5x55AI only because we have a huge quantity of it on hand and feeds better via measure. I had suspected it was a bit too hot, perhaps we'll try the reloader 22 or H450 and see if the results are better.

 

[1000yardstare]

I was going to say H380 was too fast for 140s in the 6.5 Swede in my first response but I see that the Lyman manual lists IMR 4895 and Varget for the 140s (both faster than H380) which I always thought is a little odd. I have never used anything faster than IMR 4831 for 140s in my Tikka Swede.

An F Class buddy used Varget and 139 Scenars in his Tikka 6.5x55 Varmint because it was in the Lyman manual and all the .308 shooters were raving about Varget. We told him for 2 Summers it was too fast a powder for his combo. He finally hit a hot Summer day in the 2010 Ontario Championships, started blowing primers and had to withdraw from the competition. He must have been teetering on the brink with too fast a powder and a change in one of the conditions pushed him over the edge.

 

[halfmoanut]

How about the clearence of your necks in the chamber,you should be able to push a bullet down in the necks of a fired case with very little if any resistence.I have a .269 neck and my necks are turned to .266, I had pressure with moderate loads until I got the proper clearence.

 

[BoydAllen]

I have loaded 6,5 x 55 for a lot of years, for both military and civilian and military rifles. Back when I started, the only load data that I could find was in the old black cover Sierra manual. I believe that the slowest listed powder was H380 but you should take into consideration that the test rifle was a '94 carbine, some of which had barrel extensions fitted to make minimum legal length in the US. Working up carefully, I developed loads for the most accurate light bullets with IMR 4350,and for the heavier ones with H4831. Today, we have more slow powders to choose from. In my '96 and '38 there have been two very accurate bullets, the 100 gr, Sierra, and the Hornady 160 grain. I don't care about BC because these rifles are shot with the original iron sights (not peep), so the distances at which I would contemplate using them for hunting is short enough that BC is not a significant factor. One tip for the 160 in military rifles...seat to the channalure even though they are long enough to touch. The accuracy will still be good, and you can run more powder. The 100 Sierra jumps a mile in the old military throats, but the accuracy is sub MOA with open sights, and the velocity is quite modern. Today, for the AI, I would be looking at 6.5-06, and 6.5 x .284 data, and comparing the water capacity of the cases.

 

[jonbearman]

I have the same hodgden manual and the only bullet they list with h380 is the 110 grainer's.He was way off the mark.Very dangerous and he should check the bolt for gauling or any other damage.

 

[BBTC48]

I use a standard 6.5x55 and load 50gr N160 for 120's and my newest favorite load is 47gr of RL22 with 130gr Barnes TSX. All with Fed210 Lapua brass. The 130's are at 3.030" which in my rifle is about a 40 thou jump. Last two groups equal at .385" My rifle is a LA Mod 70 with a Sako Finnlite barrel at 21 1/4" in 8" twist. Used 4831 and all the 4350s with mediocre results. N160 and RL22 have been super with this barrel length and these bullet weights. The 140's shoot to 3/4" as well as 155Megas. Check that barrel for mistaken bore size. Stranger stuff happens.