We often lament the state of quality and lack of adherence to TDP specs and tolerances in third party accessories, since we are often having to deal with them ourselves when these out of spec components cause tolerance staking issues with our in spec products.
These LDFA seconds are technically within spec and tolerances (0.312 +0.000/-0.002), but they will be a tight fit for uppers with out of spec forward assist plunger holes. In spec uppers, such as Colt and LMT will readily accept in spec LFDAs, while some billet uppers may have smaller than spec FA plunger hole. While it is an easy process to reduce/sand down the diameter and refinish the thinned down plunger body, we can't perform this inexpensively ourselves, and have no intention of selling a thus modified LDFA as new. LDFA seconds are offered for sale with significant discount, with the knowledge that it may well need to have its plunger diameter reduced to fit.
Billet construction, LDFA is machined from 4130 steel bar
stock, heat treated with black nitride finish.
Proudly designed and made in the USA.
LDFA is designed and made to TDP specs and tolerances, and to work with TDP spec upper receivers. We've seen a troubling trend, where the lack of adherence to TDP specs
and tolerances has created out of spec components, and receivers that
are also out of spec to accommodate these parts, resulting in these
receivers' inability to accept TDP spec components.
We've observed a few billet receivers with out of spec forward assist plunger hole diameter which causes LDFA, and TDP spec forward assists to have very tight fit. We've also noticed many forward assists, both "factory" with unknown origin, and aftermarket forward assists, have been significantly thinner in the plunger area. These receivers and FAs are out of spec.
Specifically, the FA housing's hole into which a forward assist is inserted has two diameters, the larger diameter hole for the plunger cap, the smaller hole for the plunger itself, These aforementioned billet receivers FA plunger holes are well short of the TDP specified diameter. LDFA's plunger measures 0.311, well within TDP tolerances. To date, we haven't seen any problems with forged upper receivers.
If you have a billet receiver, please measure the plunger hole in the FA housing. If it's less than 0.312 in diameter, LDFA will be a tight fit.