BLR Qs: light hammer strikes & peep sights

[MacEntyre]

I have a couple of questions for the BLR veterans here.

Q1:

1970 BLR .308 has a nice trigger, probably 3 lbs, making me think it has been adjusted, although previous owner thinks not. Lake City military ammo fired fine, but 7.62x51 CBC (Brazilian) ammo did not fire... got a light dimple on the primer without ignition, on two rounds in a row. I'd prefer a gun eats anything it is fed, and choose based on accuracy instead of fire/no fire. If it fails to fire cheap Brazilian ammo, is that normal, or does it indicate a weak hammer spring?

Q2:

Initially it shot low. Had to adjust the rear sight all the way to the maximum height to get her sighted in. Measured the front sight and found it to be 0.727" above the barrel. Seems high to me. Light marks indicate front sight has been changed. What is the height above the barrel of a stock BLR front sight?

Q3&4:

It's not snake bit, but is D&T for a scope. What windage and elevation adjustable peep sight works well when mounted on the rear pair of scope mount holes? What Globe sight or front sight would you recommend?

Thank you very much, folks!

- MacEntyre

[LAW483]

There is a difference in the headspace spec with an overlap. There is a sweet spot where 308 and 7.62x51 can both headspace. I have all of my M1As headspaced that way. Have your headspace checked against the 7.62mm x 51mm SAAMI Spec.

[tdoor]

I have a couple of questions for the BLR veterans here.


Q2:

Initially it shot low. Had to adjust the rear sight all the way to the maximum height to get her sighted in. Measured the front sight and found it to be 0.727" above the barrel. Seems high to me. Light marks indicate front sight has been changed. What is the height above the barrel of a stock BLR front sight?


- MacEntyre

Hi Mac-

I don't know the BLR factory front sight height, but it is easy enough to calculate a satisfactory front sight height for any gun :

To move the point of impact 1 inch at 100 yards :
1"/3600" = (change in height of sight)/(sight radius, which is the distance between front and rear sight)

change in height of sight = (sight radius) /3600

Example : for a change in point of impact of 1 inch at 100 yards, sight radius of 18":
change in height of sight = 18/3600, which is .005"

Therefore, if you are shooting 6 inches low at 100 yards, you would lower the height of the front sight by .030"

tdoor

[MacEntyre]

Therefore, if you are shooting 6 inches low at 100 yards, you would lower the height of the front sight by .030"

The front sight is fixed. I maxed out the rear sight elevation adjustment to sight it in it using a laser bore device. Clearly, the factory front sight should not be as high as it is, at 0.727" above the barrel.

I will replace both sights soon. I just want to know how high the factory front sight was.

[AJMD429]

I will replace both sights soon. I just want to know how high the factory front sight was.

Even if someone pipes up with the 'original' front sight height, there are going to be enough 'unknowns' and other variables that I think I'd just pick your favorite rear sight out first, put it on the gun, THEN replace the front, if needed. Most aperture sights either work with a stock front sight, or need one a bit higher, so yours could be perfect for a Williams FP or other such sight. When I've replaced the front with a Lyman Globe of the lowest height they sell (0.404"), it seems like it worked ok without having to raise the rear sight above what it had been set at; I usually have a Globe front when I have a 'tang' rear sight though, so there is more working room with elevation.

There is a difference in the headspace spec with an overlap. There is a sweet spot where 308 and 7.62x51 can both headspace. I have all of my M1As headspaced that way. Have your headspace checked against the 7.62mm x 51mm SAAMI Spec.

I'd like to hear MORE about all that... So far my 308 and 7.62x51 guns both seem to fire 'surplus' as well as 'commercial' ammunition interchangeably, but what should I look for to identify any problems early...???

[Pete44ru]

I mounted a Williams WGRS peep sight in the rear two scope mount holes of my 1971 BLR .358 after I removed the rear bbl open sight.

The light strikes could be laid at the feet of a cruddy FP channel - short of disassembly/cleaning, I'd suggest a power flush ot three, with a spray can of brake cleaner (protect the stock finish), through the FP hole in the bolt face.

Mine had a pretty decent, though unmeasured, trigger pull, right from Miroku - so yours might be within the range of "normal" for an early Japanese BLR.

I wouldn't recommend a globe front sight for ANY hunting rifle, and as accurate as one may be, a target rifle the BLR isn't.


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[MacEntyre]

I'd just pick your favorite rear sight out first, put it on the gun, THEN replace the front

Right... but I like to have the factory sights so I can restore it to original condition, if necessary. The rear sight that's on it now is barely useful with the front sight that's on it now.

I mounted a Williams WGRS peep sight in the rear two scope mount holes of my 1971 BLR .358 after I removed the rear bbl open sight.

That's how I want to mount the peep. Thanks!

The light strikes could be laid at the feet of a cruddy FP channel

Good idea! I'll try it.

Mine had a pretty decent, though unmeasured, trigger pull, right from Miroku - so yours might be within the range of "normal" for an early Japanese BLR.

Right, it could be the original trigger, as the previous owner believes... but it is made in Belgium.

I wouldn't recommend a globe front sight for ANY hunting rifle...

Why?

I like a globe front sight because I have one very dominant eye; the other is just along for the ride.

- MacEntyre

[M. M. Wright]

Okay MacEntyre, I took some measurements from an old Belgian that is almost like new, still has the hood on the front sight. Measured, with calipers, from bottom of barrel to top of front sight: 1.125
Diameter of barrel at this point is: .580 half of this from the overall gives .835 above bore. or .545 above top of barrel. So yes, I guess your front sight is higher than normal. I checked four of them, all the same.

Oh yeah, don't have a trigger pull gauge but all four of these are in the 4 Lb. range or less.

Q1. That Brazilian ammo may have been made for full auto stuff and have very hard primers for that. Just a thought.

[MacEntyre]

Thank you very much, M.M. Wright! I will keep my eyes peeled for a front sight that height.

Yeah, that Brazilian ammo must be one of the notorious foreign makers that use hard primers.

- MacEntyre

P.S. Did you know that Wright is a sept of the MacEntyre clan?

[Pete44ru]

I wouldn't recommend a globe front sight for ANY hunting rifle...

Why?
I like a globe front sight because I have one very dominant eye; the other is just along for the ride.
- MacEntyre

I find them to be too slow on game - and speed is one of the reasons for going to a large (ghost ring) peep - another being poor vision with open sights (more things to focus on).


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[arjunky]

Didn't read the whole thread but I had an earlier blr that had a very tight chamber, if not fully in the chamber it will not fire.

Byron

[MacEntyre]

Didn't read the whole thread but I had an earlier blr that had a very tight chamber, if not fully in the chamber it will not fire.

Thanks, but if that were the problem, the hammer would not have struck the firing pin. It chambered, the bolt was fully closed, trigger released the hammer, and the firing pin struck the round... just didn't ignite the primer and go boom.

[MacEntyre]

The light strikes could be laid at the feet of a cruddy FP channel - short of disassembly/cleaning, I'd suggest a power flush ot three, with a spray can of brake cleaner (protect the stock finish), through the FP hole in the bolt face.

Tried that this morning... tough to get much brake cleaner to go into the tiny hole.

When I depress the firing pin with my finger, it is very slow to rebound. It takes a couple of seconds to return. That can't be normal... may require a really good cleaning.

[MacEntyre]

Soaking... that's what it needed.

This afternoon I looked again, and what a difference! The firing pin spring rebounds so fast you cannot get your finger off of it before it comes back.

So, I put a new primer in a piece of brass and fired it. Here it is, next to three of the rounds that I fired on Saturday. The one that I fired today has a much larger dimple in it.

Thank you, Pete44ru!

- MacEntyre

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