[Rookie1970]

I would like to get new stock bolts for my X7VH 308W, since I have bought a torque wrench and I find hex head bolts more convenient than the ones from factory.
I've got some 6 mm. ISO bolts at home (in Spain) and thread&diameter are really close but not enough to get the right fit.
My guess is both stock bolts are 1/4" 32 TPI, but I would be very grateful if someone could confirm this point.
Besides, which grade should I buy the new ones? Is grade 8,8 good enough? Any good reasons to go for grade 12,9?
Thanks in advance for your help.

Best Regards,
Rookie1970

 

[yoteman]

I believe the threads are 30 tpi same as used in pre 70 Winchesters and many Savages. Trouble is they are not a standard bolt you can buy, if the bolt is screwed in less then 5 threads a 32 tpi bolt with moly grease on it will strech the threads but there is not enough room to strech more then 5 threads. Also a metric bolt with a .85mm pitch is close to exact to 30 tpi but the Marlin bolt is a true .25", not metric. Therefore you would have to have a bolt made up.

 

[yoteman]

I forgot to address your hardness question. It is always good to have a bolt slightly softer then what the rifle metal is. That way if something strips it will be the bolt and not the bolt hole in the rifle.

 

[GaCop]

If their the same as Savage, they'll be 1/4"X28 tpi, IIRC. I get them either at True Value or Ace Hardware.

 

[Rookie1970]

First of all, thanks for your answers. Finally I have taken a picture of the bolts and a caliper.
As far as my bad sight lets me count those 16 threads in 1/2", they seem to be 32 TPI.

 

[yoteman]

Your eyes are better than mine. I couldn't count the threads in your photo so I asked my son to count them and he said he got 15. Anyways I took the bolt out of my XL7 and put a thread gauge on them. 28 was to coarse and 32 was to fine. My gauges doesn't have 30 tpi. Also my XL7 is a JM, if your's is a Remington made perhaps Remington gets thier bolts from a different supplier and uses different threads then Marlin did.

 

[Rookie1970]

I do really appreciate your help Yoteman.
I have zoomed in the picture I took,
and you and your son are right!
There are 15 threads in 1/2" = 30 TPI.
Thanks!!
BR from Spain

 

[Rookie1970]

I have been checking the availability of 1/4" 30 TPI screws. Unfortunately, it seems 30 TPI is out of UNF, UNEF and Whitworth screw standards.

My understanding is the closer you stick to standard parts, the lower the cost of those commodities. For a manufacturer, what could be the benefit of working with non-standard screws?

 

[yoteman]

My opinion only, the cost to manufactures would be the same but they all seem to like to use parts that are mostly availabe through them. Therefore they can charge $8 for an 80 cent bolt.