I am sure by this time that many of you have heard that Alamo City Paintball is making Delrin Blazer bolts. Having just tested mine I thought I would write a review of them comparing them to the stock bolt. If there is something that is not covered in this review that you would like to see. Just post here and I will amend my initial review.
You can view the bolts here my bolt is the oringed one. ACP bolts come with x-rings instead of normal o-rings.
Dimensionally the ACP bolt is very similar to the stock bolt. Unlike the stock bolt it has a ball detent groove milled into the side. This is a nice feature for vertical feed or right feed blazers but poses a problem for left feed blazers. A left feed blazer cannot use this bolt effectively as the detent groove will allow air into your feedneck causing severe blowback. Additionally the groove is slightly too short causing the rear detent to still be compressed when the bolt is forward.
The stock bolt uses a smaller inlet hole than the acp bolt. The ACP bolt also uses an angled or ramped inlet hole rather than the simple 90 degree angle of the stock bolt. My testing revealed that these changes did not yield an increase in velocity. In fact I found just over a 10 fps drop in velocity with the delrin bolt. It should be noted that ACP did not claim an increase in velocity with their bolt and said in an email to me, "The delrin bolt with o-rings yields about the same velocity as stock. The stock bolt is of high quality/fit and it would be difficult to achieve much velocity gain with another bolt."
The other main change in the ACP bolt versus the stock bolt is in the pin design. The stock pin uses a retention system that, as far as I know, is unique to the blazer and notable for its ease of use. The ACP pin uses a design most similar to the evolution design often found in autocockers. It is very effective at retaining the pin in the bolt and I do not forsee any problems with it. It even keeps some of the character of the original bolt by having two dimples on the pin. This allows the pin to have an open and closed position while still retaining the pin. This makes putting the bolt in and pulling it out simple.
Lastly the most obvious feature, the ACP bolt is made from delrin with a delrin pin. This reduces the weight of the bolt from 42 grams to 24 grams. The stock bolt and pin are already very light but as they say, "every little bit helps." I felt that this reduced the recoil enought to be noticed, which is impressive on an already low recoil marker. The lower mass also allowed me to slightly lower my lpr pressure.
What I like:
~Inexpensive option for your palmer marker
~Service (read note below)
What I dislike:
~Initial milling error (read note below)
~Front oring hits ball detent on every stroke, already showing a nick.
Changes I would like to see made to the bolts:
~I would like to see the ball detent groove either eliminated or lengthened to fully accomodate the rear detent. I think eliminating it would be the better choice as it would allow the bolts use in left hand feed blazers and the detents on blazers are already light.
~The head of the pin on the ACP bolt is shorter then the stock bolt and I find it difficult to grasp.
~I would like the Palmer's pin retention system on the delrin bolt. It is a simple retention system and a unique plus to the Blazer's design. Plus it would further reduce the weight of the bolt by getting that metal ball bearing and spring tension bolt out of the equation. It would also allow for the adjustment of the pin position, which would be nice.
~Make the inlet port the same size as the original bolt (see update 2)
Thanks, and I hope you enjoyed,
THE NOTE: When I first received this bolt it did not work in my Blazer. This was the result of a milling error on the delrin pin. The pin's head was milled with the base of it being too short. This allowed it to slip out of the master link. A call to Alamo City Paintball had a new pin on its way to me the same day at no cost to me. They were very courteous and apologized for the error. The service was very good and they got me up and running quickly. I still think the head could extend a little further but it is perfectly functional now.
1) hs2000 has just reported that his delrin pin snapped in half on his bolt/pin combo. Updates to come.
2) I have discovered that the larger inlet hole on the bolt is actually causing a problem. The larger inlet hole means that the orings closest to the hole are farther apart. The front oring actually protrudes slightly into the feedneck, which does not happen on the stock bolt. This could be responsible for my velocity loss.