What is the size of the butler creek scope cap that I need to cover the front of the PVS-14?
Thank you

09A (Eye) is the closest match, but will need some electrical tape or something to shim it to get a real friction fit.  

~Augee

If you're referring to the objective, I would think the BC #5 should work... perhaps with some minor fitting.
http://www.amazon.com/gp/product/B0013R4CWQ?psc=1&redirect=true&ref_=ox_sc_act_title_1&smid=ATVPDKIKX0DER

Clear as mud, everyone listed a different size

I think I'd go with UNV

It was answered in the first post by Augee

<< 09A (Eye) is the closest match, but will need some electrical tape or something to shim it to get a real friction fit. >>

So I ordered the Butler creek #14 eye  for my pvs14. It was on sale at amazon for $3.99.

I think some of the confusion is what end we're talking about putting the caps on.  

If you're looking for a reduced aperture/close focus device for the objective, a la the Hoplite, but not $50 a pop, this is the 09A Eye with a thin strip of electrical tape inside the cap so that it friction fits to the objective:






UNV is talking about a flip cap for the eye-piece to protect the ocular lens.  

~Augee

09A for the DIY hoplite

9A for NEPVS-14-17

This should give you most of the basic information -

http://www.ar15.com/forums/t_6_18/399269_DARC_DIY_NVG_focus_trick.html

I just drilled the holes with a 5mm drill bit and called it good.  

~Augee

Thanks, Augee. Now I know.



 

09a + a little electric tape worked out great.
Thanks NV crew!

The best size of Butler Creek (B.C.) scope cover to use that does not require any fillers or taping to make it fit is the "07 Objective" size, B.C. item # 30070. It fits an objective size of 1.429" or 36.3mm, which so close to the acutal diameter of the objective focus ring, that it fits nice and snug w/o tape modifications. Furthermore, since it is an objective cover, it doesn't have the red "push to open lever" that an eyepiece cover has, meaning less of a chance of snagging the push lever on something or it breaking off.
The B.C. cover sits sugly on my PVS-14's and doesn't require any taping anywhere as it is the proper size. A 3/16" hole drilled in the center of the scope cover, after removing any burrs left over from drilling, is the best size hole for all around distance and close viewing.  Once the PVS14 is focused for a distance greater than 15-20 yards,  without the cover closed on the objective on the NVD, everything from about arms length & out (maybe closer depending on your arm length)  will be in almost perfect focus with the B.C. scope cover closed. Any fine focus adjustment to see absolutley sharp images up close can be done with a very small focus twist of the PVS14. However, I found I didn't need to fine adjust the focus with the cover closed as I could see the ground and objects at my feet clearly. Of course, as with all focus assist devices, closing the cover and viewing throught the small hole does reduce the light reaching the amplifier tube so a gain adjustment will have to be made if not using an IR illuminator to supplement the reduced lighting.

2nd page due to character restrictions:

One additional benefit I found to using the Butler Creek 07 size objective lens cover is that it fits better against my QD weapons mount ring I have on the PVS14 than the other commercial brand of focus assist cover. And, the cost is 1/10th the price of the least expensive commercially made model.

The commercial made models do allow for changing the hole size, as the one size drilled  hole of the B.C. cover does not allow switching to other sizes for different situations. It also does not have a scraficial lens built in as the commercial ones have. I have a commercial cover, which is very nicely made and the B.C. alternative. However,  I really like the $$ savings of the B.C. alternative. Hope this helps the NVG users looking for a solution to the PVS14 focus  quandry w/o having to resort to tape to make a cover fit.