Mopane
Super member
This is going to be a somewhat lengthy tale about the Umarex Colt M4 break-barrel .177cal. Air-Rifle. Grab a cuppa if you want.....
So I bit the bullet and ordered one of these a few months ago, to scratch an itch. I have a couple of other replica type springers that I really enjoy and liked the look and specs of this M4 replica.
It duly arrived and I was really impressed with the weight and feel out the box. A brief check over and barrel clean (really filthy) and a few shots sent down the garden range. It has a vague trigger but you get used to it pretty easily, but it's loud - a real thump and a crack, alot of fun.
It was going well, I also replaced the mag with a steel one and did a bit of 'weathering' to add a bit of realism
Now having spent some time with it, the shooting is settling in, dieseling is subsiding, so far so good.
Unfortunately with more time spent, the bad bits became apparent. The inner power plant which I believe is a Diana based springer is working well and at this stage I have no intention to open it up, and I'm good with its performance.
But the bodywork has some bits that I don't like and feel that this let's an otherwise decent looking replica down alot.
At this point I was in for the duration as despite the issues I encountered, I like the gun and wanted to stick with it....
Firstly- My rear sight leaf was canted left, due to a non concentric hole running on the adjuster bolt ! - honestly the flip up plastic unit is really cheap nasty tat. So, I got hold of a decent M4 carry handle and replaced the folding rear sight unit.
Next - The front sight unit is also plastic, looks good but with a plastic threaded sight post and is adjusted with a supplied plastic tool. Well I ran out of adjustment so needed to file down the post a little at which time I discovered I could jiggle the entire front sight unit/gas block left and right about 2mm either way -
Now this unit is 'secured?' to the barrel with a solid pin and a roll pin on the underside through the pseudo bayonet lugs with a flat surface on the topside of the barrel mounting collars to prevent the lateral movement.
I found that both plastic lugs were split from heavy handed assembly at the factory, which annoyed me....
Then the flimsy prongs on the sight post adjuster disintegrated and I decided to address the issue.
I raided the box of bits from my airsoft days and found a steel sight post and locking plunger and replaced the plastic guff. Then cut some shims to use on the 'flats' on top of the barrel mounts and carefully reinstalled the gas block and sight assembly.
Here's pics of the factory pinning - note split plastic.
New steel sight post and locking plunger fitted....
So now I had a solidly mounted gas block/front sight unit - All was good in the replica world for me.
A few summer weeks passed and I really was enjoying the Colt and started thinking about optics for a bit of variety .
I must add that I am a big fan of open sights, all my rifles run opens, mostly peep sights - only my pest control rig and target rifle have big glass , but I do have a sweet German post reticle scope on the K98.
Now I plan on getting a Colt type scope to mount on the carry handle at some point, but for now I had various red dots and a nice Vector Mustang LVPO with a chevron AR reticle..
So having a tall front sight unit is a nuisance with 1x optics - and although it's workable, it was the excuse I needed to be rid of that plastic front sight.
The front most picatinny rail on this gun is not really usable for a rear folding sight unit due to the break barrel breech block travel when cocking the rifle, plus it's only 2 slots, so not much real estate for a solid mount IMO.
I was mulling over a plan of action, death-scrolling the Web when I found a pic on Reddit of a Knights Armament Company (KAC) M4A1K - A very rare beast, with only a handful made that were supposedly intended for USAF air-crew.
Now I haven't got the ambition to chop the 15" barrel of the Umarex Colt (imagine trying to cock it!) or mess with the stock, but I liked the gas block and folding sights.
Fast forward a couple of weeks and a set of KAC sights and a new metal gas block with a rail landed.
I needed to ream out the gas block as the majority of AR available to me had 19mm block mounts, but the Umarex ones are 20mm.
After some very steady reaming with an adjustable reamer tool, and careful measurements I got a perfect snug fit and installed the new gas block.
I Fitted the sights and had an afternoon experimenting with various optic set ups,
The Red dot co-witnesses the iron sights perfectly and the 'irons' are great on their own.
So lots of cool formats to play & plink with, and really pleased with the end results- finally got it how I want it at last...(Famous last words!)
If you got this far, Thanks for reading
Happy Shooting All!
So I bit the bullet and ordered one of these a few months ago, to scratch an itch. I have a couple of other replica type springers that I really enjoy and liked the look and specs of this M4 replica.
It duly arrived and I was really impressed with the weight and feel out the box. A brief check over and barrel clean (really filthy) and a few shots sent down the garden range. It has a vague trigger but you get used to it pretty easily, but it's loud - a real thump and a crack, alot of fun.
It was going well, I also replaced the mag with a steel one and did a bit of 'weathering' to add a bit of realism
Now having spent some time with it, the shooting is settling in, dieseling is subsiding, so far so good.
Unfortunately with more time spent, the bad bits became apparent. The inner power plant which I believe is a Diana based springer is working well and at this stage I have no intention to open it up, and I'm good with its performance.
But the bodywork has some bits that I don't like and feel that this let's an otherwise decent looking replica down alot.
At this point I was in for the duration as despite the issues I encountered, I like the gun and wanted to stick with it....
Firstly- My rear sight leaf was canted left, due to a non concentric hole running on the adjuster bolt ! - honestly the flip up plastic unit is really cheap nasty tat. So, I got hold of a decent M4 carry handle and replaced the folding rear sight unit.
Next - The front sight unit is also plastic, looks good but with a plastic threaded sight post and is adjusted with a supplied plastic tool. Well I ran out of adjustment so needed to file down the post a little at which time I discovered I could jiggle the entire front sight unit/gas block left and right about 2mm either way -
Now this unit is 'secured?' to the barrel with a solid pin and a roll pin on the underside through the pseudo bayonet lugs with a flat surface on the topside of the barrel mounting collars to prevent the lateral movement.
I found that both plastic lugs were split from heavy handed assembly at the factory, which annoyed me....
Then the flimsy prongs on the sight post adjuster disintegrated and I decided to address the issue.
I raided the box of bits from my airsoft days and found a steel sight post and locking plunger and replaced the plastic guff. Then cut some shims to use on the 'flats' on top of the barrel mounts and carefully reinstalled the gas block and sight assembly.
Here's pics of the factory pinning - note split plastic.
New steel sight post and locking plunger fitted....
So now I had a solidly mounted gas block/front sight unit - All was good in the replica world for me.
A few summer weeks passed and I really was enjoying the Colt and started thinking about optics for a bit of variety .
I must add that I am a big fan of open sights, all my rifles run opens, mostly peep sights - only my pest control rig and target rifle have big glass , but I do have a sweet German post reticle scope on the K98.
Now I plan on getting a Colt type scope to mount on the carry handle at some point, but for now I had various red dots and a nice Vector Mustang LVPO with a chevron AR reticle..
So having a tall front sight unit is a nuisance with 1x optics - and although it's workable, it was the excuse I needed to be rid of that plastic front sight.
The front most picatinny rail on this gun is not really usable for a rear folding sight unit due to the break barrel breech block travel when cocking the rifle, plus it's only 2 slots, so not much real estate for a solid mount IMO.
I was mulling over a plan of action, death-scrolling the Web when I found a pic on Reddit of a Knights Armament Company (KAC) M4A1K - A very rare beast, with only a handful made that were supposedly intended for USAF air-crew.
Now I haven't got the ambition to chop the 15" barrel of the Umarex Colt (imagine trying to cock it!) or mess with the stock, but I liked the gas block and folding sights.
Fast forward a couple of weeks and a set of KAC sights and a new metal gas block with a rail landed.
I needed to ream out the gas block as the majority of AR available to me had 19mm block mounts, but the Umarex ones are 20mm.
After some very steady reaming with an adjustable reamer tool, and careful measurements I got a perfect snug fit and installed the new gas block.
I Fitted the sights and had an afternoon experimenting with various optic set ups,
The Red dot co-witnesses the iron sights perfectly and the 'irons' are great on their own.
So lots of cool formats to play & plink with, and really pleased with the end results- finally got it how I want it at last...(Famous last words!)
If you got this far, Thanks for reading
Happy Shooting All!
