Break-barrel question

Break-barrel question

Joined: May 18th, 2012, 10:50 pm

June 29th, 2012, 4:14 am #1

Commonly both iron sights (front & rear) on break-barrel rifles are mounted on the barrel - on the same plane. Assume the rear sight is mounted (peep or telescopic sight) on top of the compression chamber. Can such pivot barrel arrangement change the point of impact from shot-to-shot? Perhaps over a period of time?
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Joined: June 15th, 2012, 1:18 am

June 29th, 2012, 4:40 am #2

I have an HW30S and an HW50S. On both guns, when I first got them, I tested the alignment consistency by mounting a peep sight, while keeping both the front and breech block sights in place. This way, I can check the alignment of the three sights before I shoot.

The HW50S, with the chisel detent, had no problem. The three points aligned every time I restored the barrel after breaking it. On the HW30S, however (with a ball detent), the barrel didn't always align the same way. After some experimentation, I found that I can get consistency by pushing the barrel up one more time after it clicks straight.
Last edited by JRFArizona on June 29th, 2012, 4:42 am, edited 1 time in total.
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Joined: March 22nd, 2006, 5:11 am

June 29th, 2012, 6:14 am #3

Commonly both iron sights (front & rear) on break-barrel rifles are mounted on the barrel - on the same plane. Assume the rear sight is mounted (peep or telescopic sight) on top of the compression chamber. Can such pivot barrel arrangement change the point of impact from shot-to-shot? Perhaps over a period of time?
Properly fitted parts with good tension systems will suffer little variance. Wear induced slop will add to inconsistency. The venerable HW55 has got a locking lever to insure the minimum possible difference in position:

http://www.network54.com/Forum/79537/me ... +buttplate

-Scot
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Joined: April 18th, 2001, 2:28 am

June 29th, 2012, 10:26 am #4

Commonly both iron sights (front & rear) on break-barrel rifles are mounted on the barrel - on the same plane. Assume the rear sight is mounted (peep or telescopic sight) on top of the compression chamber. Can such pivot barrel arrangement change the point of impact from shot-to-shot? Perhaps over a period of time?
That's why they mount the sights on the barrel in the first place.

That being said, as already posted if the breech is properly tensioned and lubed, the differences will be microscopically insignificant within a single shooting session. The kind of variation you described definitely means something needs to be tweaked.

Over the long-term some tiny amount of change in barrel angle, due mostly to compression of the breech seal, can possibly occur with any barrel-cocking rifle. But this is minimal with modern materials, and should be totally neglible amongst normal adjustments for different pellets and distances.

Any such change would be so small, and so gradual, I can't imagine there's even an effective way to measure it. Bottom line: not worth worrying about!
Last edited by MDriskill on June 30th, 2012, 12:35 pm, edited 1 time in total.
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Joined: September 2nd, 2010, 1:00 pm

June 29th, 2012, 11:02 am #5

Commonly both iron sights (front & rear) on break-barrel rifles are mounted on the barrel - on the same plane. Assume the rear sight is mounted (peep or telescopic sight) on top of the compression chamber. Can such pivot barrel arrangement change the point of impact from shot-to-shot? Perhaps over a period of time?
then it has been so little that I have never noticed it over the years.

Mine has always had a scope on it since day one, have never shot it without a scope but the detent on the FWB 124 seems to be pretty dang consistent after somewhere between 20,000 to 30,000 pellets through it.
I don't see how a standard springer could really be any more accurate shot after shot year after year.
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Joined: July 24th, 2010, 1:44 am

June 29th, 2012, 12:41 pm #6

Commonly both iron sights (front & rear) on break-barrel rifles are mounted on the barrel - on the same plane. Assume the rear sight is mounted (peep or telescopic sight) on top of the compression chamber. Can such pivot barrel arrangement change the point of impact from shot-to-shot? Perhaps over a period of time?
on a daily basis, hence, the need to check/adjust your zero before shooting. The poi of a break barrel will change over time due to the mating of pivot components, however such changes occur VERY gradually unless the barrel tension is adjusted too tight or there is improper lubing. I personally don't notice any changes in the poi due to component wear simply because my guns require checking/adjusting the zero prior to shooting anyway. LOL.....I even need to re-zero my fixed barrel HW77 before a shooting session so there's no PRACTICAL difference between the two except for the "inherent accuracy" between the two springers.

Here are a couple targets I shot with my break barrel R9s while sitting on a bucket resting the gun on cross sticks (hunter class field target style).........


20 Shots at 11 yards


10 shots at 18 yards


At 30 and 40 yards testing the accuracy of Beeman FTS pellets vs CPLs.


Two 50 yard 5 shot groups with zeroing shots on the right of the sheet.


15 out of 20 shots inside a 3/4" kill zone at 50 yards shot hft style.

Anywhoo......for ME and my HW springers, the break barrel latch up consistency at a shooting session very consistent! I guess the exception to this is the Crosman Quest and the Gamo440 I owned because the pivot tension design of a "sleeve in a hole in the barrel pivot block/pivot bolt going through the sleeve/plastic pivot washers" did give erratic grouping (groups would rotate about a center point on the target), however I haven't noticed such issues with any of the HW break barrels I've owned.




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Joined: August 16th, 2008, 6:50 am

June 29th, 2012, 5:28 pm #7

Commonly both iron sights (front & rear) on break-barrel rifles are mounted on the barrel - on the same plane. Assume the rear sight is mounted (peep or telescopic sight) on top of the compression chamber. Can such pivot barrel arrangement change the point of impact from shot-to-shot? Perhaps over a period of time?
i have two Beeman break barrels...i like and shoot both and both can be accurate to the near extreme in closer ranges.

i've had the RX since approximately 1990 and it hasn't changed in it's sighting plane...however...it was knocked off of my shooting bench and bent the barrel in an upward angle...i now have it in the shop being straightened. i hope to go back to using the iron sights on it.

the R10...i shoot exclusively with optics as i dropped it and it fell directly on the rear sight elevator screw damaging it so it will not operate.

in all honesty...i prefer a side lever or under-barrel cocking, fixed barrel like my RWS Diana 52...

never squat down while wearing your spurs...will rogers
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Joined: October 21st, 2000, 9:30 pm

June 29th, 2012, 11:55 pm #8

then it has been so little that I have never noticed it over the years.

Mine has always had a scope on it since day one, have never shot it without a scope but the detent on the FWB 124 seems to be pretty dang consistent after somewhere between 20,000 to 30,000 pellets through it.
I don't see how a standard springer could really be any more accurate shot after shot year after year.
In quality airguns its pretty much a non issue.

"The Universe is comprised mainly of two things.. hydrogen and ignorance."
John Dobson
Inventor, astronomer and metaphysical thinker.
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